DROK 2-Channel Digital Car Power Amplifier 20W+20W DC 12V Rated voltage: 12 (V) Impedance :4-8() Frequency response: 20 hz-20khz Output power: RMS 20w + 20w 1khz; Treble Control: 12 db + /- 10 khz;Bass Control: 12 db + /- 100Hz