The BassLink T consists of a 10" subwoofer, two 10" passive radiators, and a 250-watt Class D amplifier housed in a rigid polymer enclosure. The enclosure is made of an acoustically inert polymer, which is rigid enough to resist flexing and dampens any resonance. This unit has a built-in 250-watt Class D amplifier, which is highly efficient and designed specifically for use with the subwoofer and passive radiator combination. When the speaker-level inputs are used, the system will automatically turn on and off with the radio. The low-pass filter frequency can be adjusted from 50 to 120 Hz The amplifier includes a continuously adjustable bass boost from -6 to +3 dB, centered at 40 Hz. Also: Phase Switch Remote Level Control Mounting Flange. Dimensions: 40-1/2 inches long 14-1/2 inches high 7 inches wide (1026mm x 164mm x 366m)