Garmin's 010-11928-20 Transom Mount 300W TM150 Transducer with CHIRP Technology. Provides a maximum depth reading of 1,500 ft. Operating frequency of 95 to 155 kHz. 26/17 degree beamwidth and mounts on a 3 to 20 degree transom. Includes 39' of Cable. Compatible with Garmin GPSMAP 527xs, 547xs, 721xs, 741xs, 840xs and 1040xs.