Rotation speed
The speed of rotation of the working nozzle provided by the tool. Some models have a fixed rotation speed, others allow you to adjust it within a certain range (see "Number of speeds").
For different types of tools and types of work, different values of this parameter will be optimal; therefore, it is worth choosing taking into account the tasks that are planned to be solved using the tool (it is best to consult with special sources). We note only a couple of general patterns. So, for engraving on relatively soft and pliable materials (wood, glass, soft metals), high speed is not required, but for hard and difficult to process (steel, precious stones), a high-speed tool is better suited. But when drilling, note that for the same power consumption (see above), more revolutions, usually, means lower torque values. That is, here “high-speed” tools are better suited just for soft materials, and low-speed tools are better suited for hard and heavy materials.
Noise level
The noise level produced by the tool during operation. For comparison, 50 decibels roughly corresponds to the noise in an office room, 60 dB to an average TV volume, 70 dB to a truck at a distance of about 8 m, 80 dB to traffic noise, 90 dB to a loud scream.
The lower the noise level, the more comfortable the use of the tool. At the same time, note that this parameter is usually indicated very approximately — the actual “loudness” of operation can vary markedly depending on the mode, the nozzle used, the material being processed, etc.
Weight
The weight of the tool can be indicated according to different rules: some manufacturers take into account only the body without a nozzle, others — with a standard working nozzle, for multi-tools (see "Device") the weight of the main unit without a replaceable head, etc. can be indicated. These points are usually specified in the specifications or detailed documentation.
In the case of a power tool, weight has a dual meaning. On the one hand, the smaller it is, the easier it is to hold the unit in your hands during long work and the more convenient it is to carry out fine, accurate processing. On the other hand, a light tool is less stable and has an increased tendency to jerk, which is important under difficult conditions and hard materials.