USCG certified for use on power driven vessels under 20 meters (65.6 ft.) in length. 2-mile visibility. Available in chrome plated bronze or white epoxy coated bronze. Uses 10% of the energy draw of standard lights. Low heat, long life and water resistant. Vertical mount. Screw size is 8. Housing Chrome Size 3-1/4" L x 2" W x 1-1/8" H Volts 12 Pack 2