Description
GT21-TM Transom Mount Transducer, Traditional 600W, 50/200kHz, ClearVü CHIRP 500W, 260 & 455kHz
Perfect for coastal and offshore fishermen who want traditional sonar and CHIRP ClearVü 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 ClearVü element has a power rating of 500W and operating frequencies of 260/455 kHz. The traditional sonar has a power rating of 600 W and operating frequencies of 50/200 kHz. It also includes a built-in fast response temperature sensor.
GT21-TM includes an 8-pin transducer with mounting hardware and installation instructions. Follow the instructions carefully to avoid damaging your boat.
WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.
Specifications:
- Temperature: Yes
- Speed Included: No
- Pins: 8
- Mounting Style: Transom
- Imaging: Standard/Down
- Chirp: Non Traditional
- Cable Length (Feet): 30′
- Box Dimensions: 5″H x 6″W x 12″L WT: 2.8 lbs
- UPC: 753759152826
Owner’s Manual (pdf)



![Garmin GT20-TM Transom Mount DownVu 500W (CHIRP 455 /800kHz) Traditional 500W (77 /200 Hz) Transducer w /Temp - 4-Pin [010-01960-00]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gt20-tm-transom-mount-downvu-500w-chirp-455-800khz-traditional-500w-77-20.webp)
![Garmin GT51M-THP SS TH Pair DownV /SideV 500W (CHIRP 260 /455kHz) Trad. 600W (Mid CHIRP 80-160) Transducers - 12-Pin [010-01966-11]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gt51m-thp-ss-th-pair-downv-sidev-500w-chirp-260-455khz-trad-600w-mid-chir.webp)
![Garmin GST 43 Thru-Hull Speed /Temperature Transducer w /GST 10 Bundle [010-04284-00]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gst-43-thru-hull-speed-temperature-transducer-w-gst-10-bundle-010-04284-0.webp)
![Garmin GT30-TM DownVu /SideVu 12-Pin Transom Mount Transducer f /GCV 10 - 20' Cable [010-01961-00]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gt30-tm-downvu-sidevu-12-pin-transom-mount-transducer-f-gcv-10-20-cable-0.webp)
![Garmin GT22HW-TM Plastic, TM or Trolling Motor Transducer, High Wide CHIRP /CHIRP DownVu - 455 /800kHz, 500W, 8-Pin [010-12403-00]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gt22hw-tm-plastic-tm-or-trolling-motor-transducer-high-wide-chirp-chirp-d.webp)
![Garmin GT30-THP SS Thru-Hull Pair DownVu /SideVu Scanning Transducer w /Temp f /Hull Deadrises 5-25 [010-01961-11]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gt30-thp-ss-thru-hull-pair-downvu-sidevu-scanning-transducer-w-temp-f-hul.webp)
