Ritchie V-537 Explorer Bulkhead Compass This Ritchie Explorer compass easily fits a 3 mounting hole and is is installed with the provided mounting screws. The brite white lettering on blue combined with the 12V night illumination allows for a readable compass in all weather conditions. Built in compensators allow for easy deviation adjustments. The compass features adjustable viewing and heel angle. Features 12V Night Illumination Reapairable Built in Compensators Easy Installation Adjustable Vi