USCG Certified for use on power driven vessels under 20 meters (65.6 ft.) in length. 2-mile visibility. White plastic top with clear fluted lens and frosted globe, and 3/4" diameter anodized aluminum tube. L.E.D.'s use less than half the energy draw of standard lights, low heat, long life. Screw size is 8. Housing White Mount Fixed Height 7-1/8" Base 1" x 2-5/8"