Echonautics BT70L300-12 300w 40-75kHz Low CHIRP 12d Tilted Element Bronze THEchonautics BT70L300 40 75kHz Low CHIRP 300watts 12 Tilted Element Model: BT70L300 12 A low profile thru hull CHIRP transducer, that matches vessels deadrise to specific angle. Designed to minimize drag and to perform at high speeds Specifications Function Depth and Temperature Frequency CHIRP 40 75kHz Mount style Thru Hull Tilt deadrise 12 tilted element ; for 8 to 15 hull deadrise Material Bronze RMS Power 300 watts Hole diameter 2. 38 in Cable