Perko's 1181DP0CHR Fold-Down Combination Masthead/White All-Round Light is certified for use on sail or power driven vessels under 20 meters in length. This Combination/Masthead light has a horizontal mount and folds down 90 degrees in either direction opposite of the plane attachment plate. This light features a zinc alloy polymer top, base and lens. It also features a 3/4" anodized aluminum tube. Two 12 volt bulbs are included with the light. The vertical height of the light is 14-1/4" and it has a base dimension of 2" x 1-1/2". The required screw size for installation is #8.