Serial No: 30402113566 Check OK 4 ch power amplifier / rated output: 75 W × 4 (1.5 to 4 Ω) 150 W × 2 (4 to 8 Ω) Frequency response: 5 Hz to 30 kHz (+0 -1dB) Input sensitivity: 200 mV to 2 V 800 mV to 8 V / high pass: 50 Hz to 5 kHz (-12 dB / oct or -24 dB / oct) Low pass: 50 Hz to 5 kHz (-12 dB / oct or -24dB / Oct) One nut missing on the left side of RCA (RCA can be connected normally) Scratches Yes 1 month warranty for peace of mind