Boss Audio - MCBK425BA 600W Motorcycle/ATV Sound System with Bluetooth - Black - MCBK425BA. Chrome 600 watt Motorcycle/ATV Sound System with Bluetooth Audio Streaming, One Pair of 3 inch Weather Proof Speakers, Aux Input and Volume Control.. Audio Streaming. Audio streaming [A2DP] is an audio protocol of Bluetooth technology. This profile allows for audio to be streamed wirelessly from your compatible device, such as a Smartphone, to the source unit so you can enjoy your favorite music or streaming music service such as Pandora or Spotify, wirelessly.. Class A/B. Class A/B amplifiers have long been known for their ability to produce great quality sound while performing more efficiently than pure Class A amplifiers. We have developed a specific linear circuitry that further reduces distortion while increasing both sound quality and power output.. Remote Volume Control. Wired Remote Control that can be installed in a convenient, safe place to allow you to control the volume of your syste