Rated power
Rated power of the acoustic system. Most often, the average (root mean square) sound power is indicated as rated.
The most obvious point related to this characteristic is the volume of sound: the more powerful the sound system, the louder the sound it can produce, all other things being equal. In addition, compatibility with an external amplifier depends on this indicator: its power should not exceed the power of the sound system, otherwise overloads and damage to the speakers are possible.
Max. power
The maximum power of a short-term (up to several seconds) incoming signal that the speaker can withstand without physical damage. Just like the nominal power, it matters for the selection of acoustics for an amplifier (or vice versa): it is believed that the maximum power of the speakers should be at least 2 times higher than the maximum power of the signal source.
Woofer size
Size of the low-frequency speaker(s) provided in the speaker system.
This size is specified only for models with separate bass speakers. In such acoustics, it is the LF emitter that is the largest (this is due to the physical characteristics of the bass range). Accordingly, the space occupied by the entire system is determined mainly by the diameter of the LF speaker. And since the power and richness of the bass also directly depends on the size of the emitter, then when choosing, you have to proceed from a compromise between the capabilities of the acoustics and the available space in the car.