This deck mount compass offers unique features unmatched by other compasses on the market. At night, a photosensitive switch automatically turns on a dim red LED light for easier nighttime viewing without nightblindness. Large easy-to-read compass markings stand out, and a suction cup mount allows for easy & secure placement anywhere on the deck. Dimensions: 3.5" dia., 4.5" height. Weight: 14.4 oz.