USCG certified for use on power driven vessels under 20 meters (65.6 ft.) in length. 2-mile visibility. Chrome plated brass top and base (3-3/8" X 2-1/4"), clear fresnel globe, 3/4" diameter anodized tube with locking collar, waterproof cap and retainer, 16 rake, and gold plated contacts. 12V bulb included. Screw size is 8.