Raymarine P79 Adjustable In-Hull Angle Transducer. Compatible hull material: fiberglass Max Power: 600 watt, Frequency: 200/50 kHz, Depth only. Easily adjusts to any deadrise angle up to 22 degrees. Transmits sound waves directly at the bottom so strong echoes are reflected back to the transducer. Can be removed in seconds for servicing or storage. Only the base piece is bonded to the hull. There is no adhesive layer under the transducer face to absorb sound energy. Simplifies in-hull installation.