Swivel cover on base protects the base socket when light is stowed away. Base extends just 3" below deck. 4"-long x 1-5/8"-wide x 1-3/8"-dia. Provides 2-mile 360°illumination for boats up to 65.6' (20m). Includes 911339 base and 9-watt wedge base lamp. Three countersunk holes for #10 fasteners.