Quick Summary
The Garmin GT21-TM is a transom mount transducer for traditional sonar and CHIRP ClearVü scanning sonar. It is described as a model for coastal and offshore fishing, with a CHIRP ClearVü element rated at 500 W and operating frequencies of 260/455 kHz.
As a transom mount unit, it is the part that sits at the stern of the boat and supports sonar scanning below the hull. If you are comparing offers, the main checks are the mounting style, the sonar type you need and the stated frequency and power figures for this exact model.
Key Details
| Detail | Verified information and buyer relevance |
|---|---|
| Brand | Garmin – useful for matching the product to the correct marine system range. |
| Model | GT21-TM – the model name to confirm before choosing an offer. |
| Product type | Transom mount transducer – fitted at the transom rather than inside the hull. |
| Sonar type | Traditional sonar and CHIRP ClearVü scanning sonar – the buyer should check this matches the display and sonar setup they plan to use. |
| Power | 500 W – an important figure when comparing like-for-like transducers. |
| Operating frequencies | 260/455 kHz – useful when comparing sonar behaviour and compatibility needs. |
What to Compare Before Buying
- Mounting style: This is a transom mount transducer, so check that a transom-mounted fitting is what you need for the boat.
- Sonar type: It combines traditional sonar with CHIRP ClearVü scanning sonar. Compare that setup with the kind of fishfinder display and sonar performance you want.
- Power rating: The stated rating is 500 W. Use that figure when comparing similar transducers rather than relying on the model name alone.
- Operating frequencies: The listed frequencies are 260/455 kHz. Check that these match the sonar frequencies you are looking for.
Before You Decide
Confirm that the GT21-TM model, transom mount format and 500 W CHIRP ClearVü specification match your boat and fishfinder setup. The key buying checks here are the mount type and the stated sonar frequencies.
