This product is either discontinued or we cannot get that from suppliers.
Garmin 010-01960-00 GT20-TM Transom ClearVu 500W, Number of pins: 4-pin, Cable length: 20 ft, Power: Traditional 500 W; ClearVü 500 W, Beamwidth: Traditional (45/15); ClearVü (2.5 @ 455 kHz) & (1.6 @ 800 kHz), Frequency: Traditional 77/200; ClearVü CHIRP 455 kHz (435-475 kHz) & 800kHz (800-840 kHz).
The Garmin GT20-TM Transom/Trolling Motor Mount Transducer is equipped with traditional sonar that operates in 77 kilohertz up to 200 kilohertz and a CHIRP ClearVu scanning sonar with 455 kilohertz frequency.