Gravity GR8CB 8" 1200W Aluminium High Performance Subwoofer - Built-in Amplifier Built-in Amplifier. 8"/20cm Active Trunk Box Subwoofer. Frequency Response: 40Hz-200Hz Darlington Class- A/B Amplifier. Variable low pass filter: 40Hz-200Hz with 12Db/Oct. Phase Shift: 0-180. Variable Bass-boost: 0-12dB RCD, variable input sensitive: 165mV-45V. External Bass Remote Control. Signal to Noise Ratio: &gt;90dB. Dimension W x H x D: 12.5" x 4.5" x 16.5 Supply Voltage: 11-15V DC. Low level input: 165mV-4.5mV. High level input: 1V-10V. Low pass filter: 40-200Hz.Fuse: 15A