Yorkville 21in 2400W Powered Subwoofer Elite Black Ozite, Carpet Integrated 3600 Watt Amplifier (Peak - 2400 Watts Program) 21-inch Woofer with 6-inch Voicecoil Max SPL 144dB Peak (135dB Continuous) High Performance Mid-Sized Subwoofer Design 33Hz - 150Hz with Adjustable HF Roll-Off