DS18 MP4TP 4 x HYDRO 4″ Wakeboard Tower Speakers 600 Watts Black with Amplifier and Bluetooth Remote Control BTRC-R The experts at DS18 have combined some of the best products for testing your favorite sounds against the elements this summer. This is a practical system with three of our best marine grade audio products that are easy to install and enjoy: (4) MP4TP/BK speakers, (1) BTRC-R BT Receiver and (1) MP.4A (4 Channels Amplifier). These products come ready to resist all the elements, water, dust, and vibrations that the world of motorsports brings