Blade width
The width of the operating tool (blade) of the clipper. A wide blade is important for head hair trimmers, as it allows you to capture more hair in one pass and cuts faster. In turn, beard and mustache clippers use narrower knives, which is useful for fine work to give facial hair the desired shape.
Power
The performance of the tool, the maximum rotation speed of the motor and how well the device handles with thick and coarse hair depends on the power of the electric motor. So, for cutting thick head hair, you need a clipper with a power of at least 15 W, the performance of such a device is usually enough to ensure a motor rotation speed of 10,000 rpm. But there are also more
powerful clippers(from 20 W). Trimmers for beards and mustaches usually need 5 W of power. Such models most often have a performance of 3,000 – 5,000 rpm.
USB charging
The ability to charge the battery of the clipper from the USB port of the computer. This function is not particularly significant when using the machine at home, but for travel it can be useful: if necessary, the battery can be
recharged from the USB port of a portable computer (laptop or tablet). In this case, the connector in the device itself can be microUSB, USB-C or branded, which will require an appropriate cable.
Material
— Metal. High-end clippers/trimmers use a metal body. Typically found in professional models, and occasionally in semi-professional ones, a metal casing ensures remarkable durability and resistance to heavy use. However, this design substantially elevates the device's weight and cost.
— Plastic. Mostly low-cost clippers/trimmers are equipped with a plastic case. The plastic case is lightweight and easy to care for. Among the shortcomings of plastic, only low strength can be noted. If you intensively use a trimmer/clipper with a plastic case, then the working surface of the device will quickly become covered with scratches and scuffs.
— Metal/plastic. Semi-professional clippers/trimmers commonly feature a combination of metal and plastic casing. These models incorporate metal with plastic inserts. This approach maintains a high level of reliability while using plastic inserts to lower device costs and enhance user-friendliness. Clippers with combined casings are versatile for both home and salon use.