Power consumption
The maximum power consumed by the fan during operation. The higher the power consumption, the higher, usually, the greater the airflow rate created by the fan, and, accordingly, the higher the performance of the device. On the other hand, power usually directly affects the price, all other things being equal.
Number of speeds
The number of preset speeds at which the fan blades can rotate. The rotation speed is usually set by pressing the corresponding button (in addition, there is also a stepless adjustment, see the relevant paragraph). Most modern models with step adjustment have three preset speeds.
Diameter
The item refers to axial fans and gives an idea of the size of the device. The larger the size, the more airflow the fan can produce at lower RPM (and therefore less noise). It is worth noting that sometimes this indicator is indicated for the blades, and sometimes it is fully indicated for the entire grill body. However, this already gives an idea about the size and capabilities of the device.
