Base dimensions: 1” x 2-5/8”. Base Mount. Vertical Height 12-3/16”. Black polymer top and base with zinc alloy, clear polymer lens. Gold plated contacts. 3 mile visibility. Use on sail or power driven vessels under 20 meters in length. 3/4”?diameter anodized aluminum tube. Base dimensions: 1” x 2-5/8”. Uses #8 fasteners. (2) 12 volt bulbs included.