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.
Total number of nozzles
The total number of working attachments supplied with the tool.
The abundance of attachments allows the machine to be used with various materials and for various types of work. At the same time, this parameter significantly affects the cost. Therefore, when choosing, you need to proceed from how important a variety of possibilities is for you - so as not to overpay for extra nozzles that turned out to be useless in fact.
Note that this item is indicated only for engravers (see "Device") - for models of other types, specific types of nozzles are given in the corresponding item (see below).
Battery capacity
The capacity of the battery that the tool with the corresponding type of power is equipped with (see above).
Capacity is essentially the amount of energy a battery can store. The more powerful the device, the more energy it needs to work and the higher the battery capacity should be so that it does not have to be charged too often. At the same time, capacious batteries have a large weight and dimensions, which significantly affects the convenience of work. Therefore, the power of the battery tool is relatively low — otherwise, too bulky batteries would have to be used.
To some extent, this parameter also determines the time that the tool is able to work without recharging. However, taking into account the fact that different models can noticeably differ in power consumption, it makes sense to compare with each other by battery properties only tools with very similar specifications — and even then very approximately.
Note that the same tool can work with batteries of different capacities — it is enough that they are compatible in terms of connectors and operating voltage. However, if you are looking for a spare battery or a replacement for a failed battery, it is best to choose a variant of the same capacity as the original one.
Charging time
The time to fully charge the battery that the tool is equipped with from a standard charger (when using other batteries or a “non-original” charger, this time may vary both in one direction and in the other).
For battery tools in general, see "Power source". And charging time data gives you an idea of how you'll need to organize your workflow and how long breaks you'll need to charge your batteries. The specific duration of the process will depend both on the capacity of the battery (all else being equal, a more capacious model takes longer to charge), and on the technologies used by the manufacturer to increase charging efficiency.
Also note that the specific meaning of this parameter also depends on the number of batteries in the kit. Recall that there are often several of them at once (see "Batteries in set"), and while one battery is working, the rest can be charged. This allows you to reduce interruptions to a minimum, and even completely do without them. But if there is only one battery, charging breaks will inevitably be required in full. This is especially true for tools with a built-in power source (in models with replaceable batteries, the situation can be corrected by purchasing additional batteries).
Charger
A device for charging the batteries used in the tool with the appropriate power supply. For models supplied with such a device, the charger model may be additionally specified in the characteristics. This information can be useful not only for finding a spare or replacement charger, but also in case the household has other cordless tools and / or batteries for them. The fact is that many manufacturers nowadays use universal batteries that are compatible with a whole set of tools from the same brand; so, for example, a complete charger may be quite suitable for a cordless grinder or drill from the same manufacturer.
On the other hand, a lot of modern cordless tools come
without a charger at all. This option will be optimal, first of all, if a compatible memory is already available, and there is simply no need to overpay for a second device. In addition, the lack of a charger will be appreciated by those who want to choose this accessory separately, without relying on the manufacturer's decision.
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.