Comparison Casio A-158WA-1 vs Casio Pro-Trek PRG-240-1

A caliber can be described as the type of movement used in a watch. It is expensive and impractical to design a unique movement for each watch model, so most manufacturers often use the same movement in different watch models, sometimes with significantly different designs. The term "caliber" is due to the fact that initially the type of movement was designated by a number (in inch lines) corresponding to its largest size; however, today unique names or alphanumeric indices that are not directly related to sizes are widely used.

Knowing the name of the caliber on which the watch you are interested in is built, you can, if desired, find more detailed information about the mechanism and determine how its characteristics meet your requirements.

The accuracy of the rate is usually determined by the largest error — the deviation from the reference time, which can occur in a month when the watch is constantly running in normal mode. Accordingly, the smaller the number in this paragraph, the more accurate the clock. In addition, the accuracy of the movement is a kind of status indicator: if the error exceeds the values stated in the characteristics, this may indicate a malfunction in the mechanism.

If the accuracy indicators are the same both in advance and in lag, one number is indicated in the characteristics — for example, 30 sec / month (i.e. +/-30 sec / month); however, many mechanisms have unequal deviations, for example -15/+25 sec/month. Also note that this parameter is relevant only for quartz watches (see “Movement type”): in mechanical models, the accuracy of the rate is noticeably lower, it is measured in seconds not per month, but per day.

The power source of a quartz watch (see "Movement type") — in other words, the type of power source used in it.

— Battery. A miniature battery, usually in the form of a characteristic "pill"; used exclusively in quartz watches (see "Movement type"). The main disadvantage of this option can be called the need for replacement when the charge is exhausted; at the same time, almost all replaceable elements of miniature standard sizes used in wristwatches are produced only in the format of disposable batteries, without the possibility of recharging. On the other hand, they provide a long time of work, are inexpensive and are sold almost everywhere.

— Solar battery. Power supply system consisting of a photocell and a built-in battery. The photocell generates electricity when exposed to bright light, and the battery stores this energy and feeds the watch mechanism. The convenience of such models lies in the fact that with the regular presence of solar (or at least bright artificial) light, the owner does not have to worry about the energy reserve. On the other hand, the photocell significantly affects the price, and if you constantly stay indoors or wear clothes with sleeves that cover your watch, it becomes practically useless. Therefore, this option has not received wide popularity, and it is worth paying attention to such models primarily because they are regularly and a lot outdoors and/or in...bright daylight.

— Autoquartz movement (“kinetic”). A kind of automatic winding (see above), used in quartz watches. This technology was originally released by Seiko under the name "Kinetic", but nowadays it can be found in other manufacturers. Anyway, such systems work similarly to mechanical self-winding — transforming the energy from the movement of the user's hand into the energy necessary for the operation of the mechanism. However, in this case, such a mechanism does not start the spring, but rotates a miniature generator that generates electricity. The resulting charge is stored in a special capacitor and used to operate the quartz movement. Models with such mechanisms are positioned as "quartz watches in which you do not need to change the battery", and in general it is so. At the same time, they have the same limitations as conventional self-winding devices — in particular, with a sedentary lifestyle, this technology is practically useless. Yes, these watches are quite expensive.

An indicator showing how long the watch can run without winding, changing the battery, recharging, etc. It is found in models with any type of mechanism (see the relevant paragraph). Although the power reserve indicator is quite approximate, it still makes it easier to monitor the status of the device and reduces the risk of being left without a working watch at the wrong time.

Note that the End Of Life function (see below) in this case is not considered a power reserve indicator, although its role is generally similar.

— Alarm clock. A classic alarm clock is an audible signal that works at a time specified by the user. It can be used not only for getting up, but also as a reminder of a particular event. Note that in mechanical models (see "Type of mechanism") this function is almost never found.

— Stopwatch. A traditional stopwatch is a function that allows you to measure time intervals with an accuracy of seconds, or even fractions of a second. In modern watches, you can find two types of stopwatches. The first is the solutions used in models with displays (in other words, in watches with electronic and combined dials). In such devices, the countdown of seconds is displayed on the screen and is accurate to a tenth or even a hundredth of a second; Also, such stopwatches can have various additional functions: counting intermediate results for control points or laps, saving the results of the last measurement, etc.
The second type of stopwatch found in the arrow dials is the arrow on the main axis, which can be started and stopped at the request of the user. This is a rather rare option — for the reason that most often such an arrow is used in combination with additional scales and is no longer a stopwatch, but a chronograph (see below). And in watches where there are no chronograph scales, a rather unusual format for the operation of such a hand can be provided: in normal mode, it works like a standard second,...and when the watch is switched to stopwatch mode, it moves to zero and stops before the countdown begins.

— Timer. Countdown function; at the end of the countdown, an audible signal sounds. This function is convenient in cases where you need to measure a strictly defined period of time — for example, when cooking in the kitchen: “starting” the timer for the desired period is much more convenient than counting the hour you need to set the alarm.

— Day of the week. Ability to display the day of the week on the watch face. It is found both in watches with displays and in purely analogue models — they use a mechanical indicator for 7 days.

— Day of the month. The ability to display the current day of the month on the clock face. It can be either a number on the display or a mechanical indicator in the form of a window with a number. Note that in the latter case, regular adjustment of the calendar is required: the mechanical pointer is designed for 31 days, and if there are less than 31 days in the past month, the displayed date will have to be “scrolled” forward.

— Month of the year. Ability to display the current month on the watch face. Usually, it is combined with an indicator of the day of the month, and often also the day of the week; thus, the presence of this pointer means that the watch is equipped with a full-fledged calendar. Most often, the display is responsible for this function, but there are also purely arrow models with similar equipment. The month indicator of the year is often synchronized with the day indicator — so that the watch itself determines how many days are in the current month and after which day you need to switch to the first number.

— World time. The ability to use the clock to determine the time in other time zones than the current one. The specific way in which such a function is implemented may vary. Thus, the most popular option in hand models (see "Dial type") is the presence of an additional dial, on which the time of the time zone of interest is set. This format is convenient in cases where you constantly have to deal with a certain region — for example, to communicate with relatives or business partners from a particular country. Another option is the indexes on the rotating bezel (see below), corresponding to the main time zones of the world; to determine the world time, you need to turn the bezel so that the current time zone is opposite the hour hand — then the remaining marks will be opposite those divisions of the dial that correspond to the time in these time zones. This format is convenient for frequent change of time zones — in particular, it is found in watches for sailors. And models with digital dials usually provide switching the screen between the current and additional time zone (zones).


— 12/24 hour time format. This feature is indicated only for watches with pointer dials (and certain pointer-electronic models, see "Dial type"). It means that in addition to the main 12-hour scale, the watch also has a small dial with 24-hour markings. It allows you to determine what time the main scale shows — before or after noon: for example, at 6 pm the main dial will indicate 6 o'clock, the additional one — at 18 o'clock. — for example, in the conditions of a polar day / night, or during a long stay underground.
As for watches with electronic dials, even the 12-hour format is supplemented with the note "AM" or "PM" ("am" and "pm" respectively); for example, 20:00 would be 8:00 PM. So in such models there is simply no need to provide special functions for determining the time of day.

— The phases of the moon. The presence of an indicator in the watch that displays the current phase of the moon. Many processes on Earth depend on the phases of the Moon (in particular, the general physical and mental state of people), a number of signs are associated with them — not always 100% reliable, but not having an unequivocal refutation. A separate category of watches with a lunar calendar — "fishing" and "seafaring" models; the latter may even provide a separate tide calendar.

— Chronograph. Analogue of a stopwatch used in watches with pointer dials (see "Dial type"). Such watches have several additional small scales, each of which performs its own function. For example, one of these scales can be responsible for counting minutes (up to half an hour), the second — for counting hours (up to 12 hours), the third is the usual second hand, and the hand for counting seconds is located on the central axis and remains stationary until the chronograph is turned on.

— Tachymeter. A device for measuring the speed of movement by the time during which the measured section was passed. The tachymeter most often has the form of an additional scale for a stopwatch, and to measure the speed, you need to measure the time it takes to pass the control section with a stopwatch and see what number on the tachymeter scale the stopped arrow points to. In this case, the measurement time should not exceed a minute (otherwise the arrow will go to the second circle, and the readings will be unreliable), and additional calculations may be required to determine the final result. However, anyway, it is much more convenient to use tachymeter data to determine speed than stopwatch readings.

— Slide rule. Built-in mechanical calculator for some simple mathematical calculations, primarily multiplication and division. Such a device can be useful, in particular, for calculating travel time, fuel consumption, transferring money from one currency to another, etc. In hours, a slide rule usually consists of two rings with divisions (hence the second name for this function is a calculator ring ). One of these rings is motionless, and the second rotates freely; combining the marks on both scales according to certain rules, the user gets the desired result. Note that the slide rule is not as accurate as an electronic calculator and is more difficult to handle; on the other hand, with a minimum skill, elementary calculations on it can be carried out much faster than on the same calculator.

— Compass. A traditional compass is a device for determining cardinal directions. The accuracy of built-in compasses is usually not high, but they can be very useful for simple tasks or as a last resort when other navigational devices are not available.

— Altimeter (altimeter). A device for measuring the current height of the terrain. Often combined with a barometer (see below), in such cases the difference in pressure between the reference level and the current location is used to measure altitude. Technically, in this way it is possible to measure the height both above sea level and relative to a certain place taken as a standard; actual altimeter capabilities vary by watch model. Watches with this function are designed primarily for climbers and mountain hikers.

— Thermometer. Thermometers in watches are usually designed to measure the temperature of the surrounding air. This feature is found mainly in advanced sports models. It can be useful both for a general assessment of the environment, and for specific tasks such as weather forecasting, calculating the current altitude, etc.

— Barometer. A device for measuring atmospheric pressure. Data from the barometer allows you to assess the weather conditions and their favorableness for a certain type of activity — in particular, fishing. In addition, they can be used to predict changes in the weather: for example, a sharp drop in pressure is often a sign of an approaching storm. Also, the operation of the altimeter (see above) is often based precisely on the readings of the barometer.

— Bluetooth. The Bluetooth wireless interface is designed to communicate between various electronic devices over relatively short distances — up to 10 m. In wristwatches, it is mainly used to communicate with a smartphone or other gadget. The functionality of such a connection may be different, but anyway, it is much narrower than in smartwatches. The most popular features include displaying notifications from Facebook and/or Twitter on the watch, using the watch as a remote control for music or video, as well as setting the world time (determining the time zone from data from an external device).

— GPS module. Built-in satellite navigation module that allows you to determine the current geographic coordinates of the device. How this data is used may vary depending on the watch model. So, in some models, data on time zones in different countries are sewn in, and based on the current coordinates, the device can determine the exact local time. Another option is to record the routes (tracks) traveled. Some watches use GPS data for altimeter operation (see related paragraph). Models with Bluetooth may provide the ability to work as an external sensor for a smartphone or other gadget (it is believed that the hand position of the sensor improves accuracy). But it is difficult to provide full-fledged navigation in traditional watches; wearable gadgets with such functionality usually refer to either smartwatches or specialized navigators.

— Synchronization by radio channel. This function allows the watch to receive special time radio signals. These signals are transmitted over a special dedicated channel several times a day, and the exact time data is received from atomic chronometers used in scientific institutes. The error of such chronometers is 1 second for several thousand or even millions of years; accordingly, the accuracy of the clock synchronized with them is almost absolute. At the same time, note that precise time radio signals are not available in all countries of the world — so before buying such a watch, it's ok to check whether they will work in your region.

— Chronometer. In this case, the designation "chronometer" is used for high-precision models that are certified by the Swiss Chronometer Certification Centre (COSC). To obtain such a certificate, a watch must pass a fairly rigorous test, checking not only for overall accuracy, but also for the ability to maintain it with changes in case position and ambient temperature. At the same time, it should be noted that in fact "chronometric" accuracy is required extremely rarely, and it affects the cost of watches quite noticeably. So compliance with the COSC requirements is not so much a practically significant moment as an indicator of the high class of watches and the status of their owner.

— Pedometer. Built-in counter of the number of steps taken by the user. This feature is found predominantly on sport touring models equipped with Bluetooth (see above) and digital or combination watch faces (see "Dial Type"). To count steps, usually, data from the built-in accelerometer is used, and the measurement results can at least be transmitted to a smartphone or other gadget, and in some models they can also be displayed on their own screen. However, it's ok to clarify the specific features of the functionality of a watch with a pedometer separately.

— Phone search. Feature exclusive to Bluetooth models (see above). In accordance with the name, it facilitates the search for a “lost” phone located in close proximity (for example, forgotten in one of the home rooms): just give a command from the clock and the device will “respond” with a sound signal. Usually, to use this function, you need to install a special application (other additional functions are usually implemented through it, if available — for example, a pedometer).

The shape of the watch case; most often the dial has the same shape, but there are exceptions (for example, a rectangular display in a round case).

This parameter practically does not affect the functionality, so the choice in this case is related solely to how convenient and pleasant-looking one or another option is for you. Also, shape data can be useful if the watch is chosen as a fashion accessory that plays a well-defined role in the image being created. As for specific options, round cases are the most common nowadays — they are easy to manufacture, look neat and fit almost any style of watch. Rectangular watches are also quite popular, they can also belong to different styles; however, such cases are more bulky than round cases, and therefore are used less frequently. The square shape is actually a variation of the rectangular shape. Oval is considered to be suitable primarily for women's watches, although there are also single men's models with such cases. There are other types of cases — polygonal, barrel-shaped, as well as products in non-standard design.

— Brass. Inexpensive material used mainly in watches of the corresponding price category. The composition is an alloy based on copper and zinc. Brass bodies have a pleasant golden colour, but their resistance to corrosion is usually very low. Because of this, such watches darken very quickly, and oxides can stain the wearer's skin and even lead to irritation. To correct the situation, various protective coatings, stainless steel covers, etc. can be used; however, even these measures are not able to completely eliminate this drawback.

— Stainless steel. Inexpensive and at the same time very practical material found in watches of all price categories. "Stainless steel" looks good, perfectly resists corrosion and scratches, retains its presentation for a long time and does not cause allergies. However it has a rather large weight, but for many users, the massiveness of the watch is an advantage, not a disadvantage.

— Titan. Premium material used in watches of the corresponding price level. Titanium alloys combine lightness and high strength, in addition, they are less thermally conductive than steel, due to which they do not “cool” the hand. They are practically not subject to corrosion, do not require protective coatings and are hypoallergenic. On the other hand, such cases are quite sensitive to scratches.

— Plastic. Common features of all types o...f plastic are ease of processing, relatively low cost, low weight, hypoallergenicity, moisture resistance and poor thermal conductivity. For a number of reasons, this material is considered optimal primarily for sports watches, including “diving” (waterproof) watches. At the same time, it should be noted that many types of plastic are used in modern watches, including high-strength varieties that are not inferior in reliability to steel. Therefore, this material is found in all price categories, from low-cost to top; The quality of the case is usually directly related to the cost of the watch.

— Aluminium. "Watch metal", considered a little more advanced than stainless steel. The aluminium alloy is also durable, resistant to corrosion and scratches, and has a solid appearance. At the same time, on the one hand, it is noticeably lighter, on the other hand, it is more expensive.

— Copper. By itself, copper has a pleasant reddish-brown tint, but it does not tolerate prolonged contact with the skin — the surface begins to oxidize, which leads not only to skin contamination, but also to irritation. Therefore, this material is usually used in combination with protective coatings. In fact, it has no advantages over the same "stainless steel", and therefore it is used quite rarely — and not so much for practical or even aesthetic reasons, but in order to distinguish watches from other models.

— Carbon. Composite material, in fact, is high-quality plastic: carbon fiber strands filled with polymer filler. Carbon is notable for its combination of low weight with very high strength; in general, it surpasses even steel in reliability; at the same time, it has many advantages of plastic, such as moisture resistance and low thermal conductivity. The disadvantage of such housings, in addition to high cost, is sensitivity to point impacts.

— Ceramics. Ceramics are various materials obtained by sintering and firing at high temperatures. Watch cases are usually made of high-quality ceramics, which are distinguished by their solid appearance and very high scratch resistance, and they cost accordingly. At the same time, they are quite sensitive to shocks, so a ceramic case is often combined with a stainless steel or other metal back cover.

— Gold. The case is made of jeweler's gold or has a gold-plated finish. Note that the colour of such a case can be different: in addition to the classic yellow, there are also white and red gold. Anyway, such watches are very expensive, and look accordingly; they are designed mainly for those who need not so much a device for determining the time as a rich fashion accessory.

— Silver. Although cases made of silver jewelry are much cheaper than gold ones, this material still belongs to the status ones, and is used not so much for practical reasons, but as a symbol of the high cost of watches and the wealth of their owner. However, for a number of reasons, silver has not received much popularity in watches.

— Wolfram. Tungsten alloys are not cheap, but they are very strong and reliable, and also look stylish. Another feature of this material is its very high melting point; from the practical point of view, this point is not significant, but it is important as a fashion detail, emphasizing the high reliability of tungsten. At the same time, for a number of reasons, such alloys are not widely used in watches.

— Bronze. Quite a rare and specific option, used similarly to copper — in order to give the watch a stylish look. The basis of bronze, in fact, is copper, and tin is most often added to this alloy, but other components can also be used. Accordingly, the colour of such material can be different — yellowish, reddish, brown.

The main colour of the watch case.

Modern watches are quite diverse in colour options. The most widespread models are in shades of " stainless steel ", golden and black ; however, in addition to this, on the market you can find, in particular, white, yellow, green, brown, red, orange, pink, silver, grey, blue and purple cases.

In general, the colour of the case is a fairly obvious parameter; Let's note only some of the nuances associated with marking:

— Multi-coloured models include models in which there is no clearly defined primary colour. If there is such a colour, it is indicated in the characteristics. And for two-tone cases, an additional colour can be specified, for example, "stainless steel with gold " or "black with blue "

— Silver, among other things, are plastic cases without additional coloring.

— "Stainless steel" in this case is a colour, not a material; other metals (e.g. alumin...ium and titanium) that are not complemented by PVD coating (see “Case Coating”) may have this shade. And the cases of gold watches, in turn, are not necessarily made of gold — red and white gold are also used in jewelry.

— Camouflage coloring is indicated separately — such watches are designated as "military", and here, again, the main shade of the coloring is given. However, not every military model has camouflage on the body; see below for details.

The material of the transparent coating covering the dial.

— Plastic. Transparent plastic (also known as "plexiglass", also known as "organic glass") is considered the simplest option and is found mainly in models of the initial and middle price range, mainly sports and tourist specialization. This material is lightweight, inexpensive, and also tolerates shocks and falls well: with a strong impact, it will crack rather than break, and plastic fragments are much safer than glass ones. These properties are indispensable for shockproof watches. On the other hand, plastic is very sensitive to scratches and tends to become cloudy quickly due to scratches; and in general it gets dirty more easily than glass.

— Mineral. Mineral in this case means ordinary, widespread glass — like the one used in windows. It favorably differs from plastic in high hardness: to scratch such material, you need to make considerable efforts. As a result, mineral glass varieties do not become cloudy and remain transparent for almost the entire life of the watch. Among the shortcomings, brittleness can be noted: upon impact, the glass surface can shatter into fragments. On the other hand, even for ordinary glass, such a blow should be quite strong; in addition, manufacturers often use various design solutions (“dial” recessed into the case, tempered glass, etc.) in order to reduce the ri...sk of such an accident to an absolute minimum. Thanks to all this, mineral glass has become widespread today in all types and price categories of watches.

— Sapphire. Glass made of artificially grown sapphire (transparent corundum — aluminium oxide). The main advantage of this material is the highest scratch resistance: such a surface can only be scratched with a diamond or a material similar in hardness to it. On the other hand, sapphire crystals are not cheap, but they do not withstand shocks well and are relatively unsuitable for "protected" watches. As a result, this material is found mainly in rather expensive models designed for everyday use (although there are exceptions).