Garmin GT21-TM Transom Mount Downvu Transducer

Garmin GT21-TM Transom Mount DownVu Transducer is crafted for coastal and offshore anglers who demand both traditional sonar and CHIRP ClearVü scanning sonar. This transom-mounted unit delivers clear, crisp fish arches with superior target separation and precise definition of structures below the boat, so you can mark fish, cover, and non-target objects with confidence.

The CHIRP ClearVü element provides vivid underwater imaging with a 500 W power rating, operating at 260 kHz (245-275 kHz) and 455 kHz (445-465 kHz). Pair it with traditional sonar, which runs at 50/200 kHz with a 600 W power rating, and you’ve got a complete view of the water column from near-field to far-field. A built-in fast-response temperature sensor adds real-time depth and temperature context to your readings, helping you locate active zones and optimize lure choice.

GT21-TM includes an 8-pin transducer with mounting hardware and installation instructions. Follow the provided guidance to ensure secure mounting and optimal performance, helping you protect your boat while maximizing sonar clarity.

Key specifications

• Traditional sonar: 50/200 kHz | Power: 600 W
• CHIRP ClearVü: 260 kHz (245-275 kHz) & 455 kHz (445-465 kHz) | Power: 500 W
• Beams: Traditional 40°/10°; ClearVü 2.0°x51° @ 260 kHz and 1.4°x29° @ 455 kHz
• Maximum depth: Traditional up to 1,500 ft; ClearVü up to 1,000 ft
• Depth/Speed/Temperature: Built-in fast-response temperature sensor
• Cable length: 30 ft
• Transom compatibility: 0°–70° deadrise/transom angles
• Includes: 8-pin transducer, mounting hardware, installation instructions

What's in the box

• 8-pin transducer
• Mounting hardware
• Installation instructions

Engineered for reliability and ease of installation, the Garmin GT21-TM Transom Mount DownVu Transducer helps you locate fish and underwater structures with clarity and confidence, letting you fish smarter and more profitably on every outing.