The Garmin GT21-TH is a stainless steel stem thru-hull transducer built for coastal and offshore fishing, combining traditional CHIRP sonar with CHIRP ClearVü scanning sonar. The result is sharply defined fish arches, strong target separation, and clear structure imaging directly beneath the hull — all from a single transducer installation.

Specifications:

• Transducer model: GT21-TH
• Mount type: Thru-hull with stainless steel stem
• Traditional sonar power: 600W
• Traditional sonar frequencies: 50/200 kHz
• CHIRP ClearVü scanning sonar power: 500W
• CHIRP ClearVü frequencies: 260/455 kHz
• Built-in fast-response temperature sensor
• Suitable for hull deadrises less than 25 degrees
• Connector: 8-pin transducer plug

In the Box:

• GT21-TH transducer with stainless steel stem
• Fairing block
• Isolation plate and bushings
• Mounting hardware
• Installation instructions

Resources:

• Owner's Manual (PDF)

⚠️ California Prop 65 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.