The BT-KIT4-B provides the ability to have stereo sound on small watercraft such as Jet Skis, inflatables or tenders. The waterproof ME-60BT Amplifier can be mounted underneath a seat or inside the boat’s structure. The Bluetooth™ enabled control head can be mounted on the dash or inside the stowage compartment – wirelessly controlling an iPhone MP3 player or other device. And with the included Poly-Planar MA-4055 5” Waterproof Speakers, you’ll have crisp, clear stereo sound on the go!, Powers up to (8) 4 ohm speakers., Internal distortion limiting circuits., Dedicated subwoofer gain level control., Rear channels switchable from full range to powered sub out., This kit comes with black speakers.