Bazooka MC-HON-AK4 4-Inch 4-Channel Coaxial Honda Amplifier The MC-HON-AK4 motorcycle audio kit works on all GL1800 bikes. Year models 2006 and prior Includes auxiliary output plug for an optional amplified BTA6100 Bazooka bass tube subwoofer that can be installed into the trunk. (BTA6100 and FAST-HON-SIK subwoofer installation kit sold separately) Plug and play interface harness 200-watt max power amplifier