Made of mica-polypropylene, these marine speakers are built for added protection against the elements associated with boating. Marine coaxial speakers feature santoprene surround and are available in two woofer sizes, 6 1/2"dia. or 7 3/4"dia. with 1"dia. titanium/PEI tweeter to provide great sound quality. Each handles up to 180W of peak power. Subwoofers are designed to withstand vibration and temperature changes, as well as exposure to moisture and salt air. Each handles up to 400W of peak power for thick, powerful bass.