This unit fits in a standard 2 1/8" (54 mm) hole used by most marine equipment manufacurers. Mounting The LDT-3003 mounts in any dash or flat panel that's at least 2 1/2" (64 mm) in diameter. To mount the unit, first make certain there is at least 3 3/4" (95 mm) from the front of the dash to any obstruction behind the dash. Also, be sure there is room to route the power and sensor cables. The maximum usable dash thichness is 1 1/8" (28.5 mm). 3 3/4" minimum TIGHTEN THESE SCREWS 12345671234567123