Number of height settings
The number of cutting height settings provided by the lawn mower. The more such settings (with the same adjustment range) — the more accurately you can choose the mowing height. Note that in some robots (see "Type") this number reaches 30 or more with a range of 30 to 60 mm; in other words, you can select the height to the nearest millimetre.
Bag volume
The volume of the grass clipping bag supplied with the lawn mower. Manufacturers select this volume depending on the power, performance and overall level of the unit, however, similar models may differ in this indicator. In such cases, it is worth considering that a larger bag takes longer to fill and needs to be unloaded less often, but it weighs more and takes up more space (even when empty). Mostly the difference in the volume of the bag is 5 liters and there are
lawn mowers for 35,
40,
45,
50, 55,
60,
65,
70 and more liters.
Full bag indicator
Indicator indicating the degree of filling of the bag. The design and capabilities of such an indicator can be different: for example, in some models it only gives an overflow signal, in others it allows you to determine the amount of grass in the bag at any time. However, anyway, this function provides additional convenience: it allows you to evaluate the fullness without removing the bag and without interrupting work.
Deck material
The material from which the deck is made is a protective casing that covers the cutting tool of a lawn mower or trimmer. In modern mowers there are such options:
— Plastic. The cheapest and at the same time the least durable material.
— Aluminium alloy. The most advanced option: these decks are durable, lightweight and less prone to corrosion, but quite expensive.
— Steel. It has greater strength than aluminium alloy and costs less, but is heavier and more prone to corrosion.
Noise level
The level of noise produced by the device during operation. Usually, a certain average indicator is indicated in the characteristics — in the standard mode of operation; however, the actual values usually do not differ much from the claimed ones.
The lower the noise level, the more convenient the unit to use and the less tired the operator. In the case of lawn mowers, this is especially true, since such equipment is quite noisy — even the quietest models (some robots) give out about 47 – 48 dB, which is comparable to talking at an average volume. Note that the decibel is a non-linear quantity, and it is easiest to evaluate the actual loudness using comparative tables. Here is the simplest table for the values found in modern lawn mowers:
— 60 – 65 dB — talking in raised tones at a distance of about 1 m;
70 dB — loud conversation of several people at the same distance;
75 dB — loud laughter at a distance of 1 m;
80 dB — motorcycle engine, medium power vacuum cleaner.
90 dB — loud screams, freight car at a distance of 7 – 10 m;
100 dB — a subway train or a loud car signal at a distance of 5 – 7 m, an industrial workshop;
110 dB — tractor engine at a distance of about 1 m.
In addition to subjective sensations, there are specific sanitary standards that limit the impact of strong noise. So, according to European standards, noise of 85 dB is allowed to be heard without protective equipment for 8 hours, 91 dB — 2 hours, 97...dB — half an hour, and 103 dB — only 7 minutes. So when choosing a unit, you should take into account the duration of work with it — with high noise, you may need protective headphones.
