"This unique dual temperature depth sounder has all the same features as the standard Faria digital depth sounders plus it reads both air and water temperatures from 32 F to 200 F. Mounts in a standard 2 1/16" diameter gauge hole and reads depth to 199 feet, 61 meters, or 32 fathoms with both deep and shallow water alarms. Keel offset allows you to program the unit to read the depth from the keel of the boat for better accuracy. The 2-line, backlit display is easy to read in all conditions."