Garmin GT21-TM Transom Mount Transducer, Traditional 600W, 50/200kHz, ClearV CHIRP 500W, 260 455kHz [010-01962-00]GT21 TM Transom Mount Transducer, Traditional 600W, 50 200kHz, ClearV CHIRP 500W, 260 & 455kHz Perfect for coastal and offshore fishermen who want traditional sonar and CHIRP ClearV scanning sonar. This transom mount transducer consistently displays clear and crisp fish arches with superior target separation as well as clear definition of structure below the boat. The CHIRP ClearV element has a power rating of 500W and operating frequencies of 260 455