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 B265LH Bronze Thru-Hull Mount Transducer w /Depth & Temp - 12-Pin [010-12379-20]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-b265lh-bronze-thru-hull-mount-transducer-w-depth-temp-12-pin-010-12379-20.webp)
![Garmin GT51M-TH SS TH DownV /SideV 500W (CHIRP 260 /455 kHz) Traditional 600W (Mid-Band CHIRP 80-160) Transducer - 12-Pin [010-01966-10]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gt51m-th-ss-th-downv-sidev-500w-chirp-260-455-khz-traditional-600w-mid-ba.webp)
![Furuno SS75M Stainless Steel Thru-Hull Chirp Transducer - 12 Tilt - Med Frequency [SS75M/12]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/furuno-ss75m-stainless-steel-thru-hull-chirp-transducer-12-tilt-med-frequency-ss.webp)
![Garmin GT23M-TH Stainless Steel, TH Mount Transducer, Mid-Band CHIRP /CHIRP DownVu - 260 /455kHz, 500W, 8-Pin [010-12404-10]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gt23m-th-stainless-steel-th-mount-transducer-mid-band-chirp-chirp-downvu-.webp)
![Garmin GST 43 Thru-Hull Speed /Temperature Transducer [010-04283-00]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gst-43-thru-hull-speed-temperature-transducer-010-04283-00.webp)
![Garmin GT30-TH SS Thru-Hull DownVu /SideVu Scanning Transducer w /Temp f /Hull Deadrises Less Than 5 [010-01961-10]](https://www.bestmarinewiring.com/wp-content/uploads/2026/08/garmin-gt30-th-ss-thru-hull-downvu-sidevu-scanning-transducer-w-temp-f-hull-dead.webp)