S-Series amplifiers are your sound systems workhorse. With unmatched reliability and budget-friendly prices, these amplifiers are the better choice in performance value. The optional RUX-KNOB.2 remote bass control knob plugs right in to select Alpine amplifiers for quick direct subwoofer control to make bass adjustments on the fly. (1) Alpine S-A60M 600 Watt RMS Mono Car Audio Amplifier Subwoofer Amp Class-D. (1) Alpine RUX-KNOB.2 Remote Control Bass Knob For Select Alpine Amplifiers Amps. Specifications: Alpines Class D Amplifier Circuit. CTA-2006-B Power Rating: 330W RMS x 1 (4ohm, 14.4V 1% THD+N); 600W RMS x 1 (2ohm, 14.4V 1% THD+N) S/N ratio: >85dB (ref: 1W into 4 ohm), >105dB (ref: rated power into 4 ohm). THD+N 0.03% (ref 1W info 4 ohm). Frequency Response: 10Hz-400Hz (+/-3 dB). Damping Factor: > 1000 Remote bass knob compatible (requires RUX-KNOB.2, sold separately)