Digital depth gauges complete with either transom mount or in-hull transducers. 600 Ft. maximum depth range. Mounts in 2-1/8" diameter opening. Backlit LCD numbers express depth in feet. Adjustable shallow alarm. 200 kHz operating frequency. 12V D.C. easy to install. Comes complete with mounting hardware and instructions. Transducers have 16 degree cone angle, and 20' cables. (In-hull not for aluminum boats).