This EnrockMarine Universal USB AUX port allows for connection of external storage device, For use with any stereo with USB capability and/or auxiliary audio inputs, 1/8 audio jack allows input of any MP3 player or external audio device, Audio connector (RCA) 6 ft. cable length ASTM B117 salt spray exposure standard compliant, ASTM D4329 UV exposure standard compliant, Through hole mount with threaded housing and knurled securing nut, Waterproof design, Mounting Hole: 1.5, Dimensions: 1.89 diameter x 1.18 depth