This unit has been discontinued - Try the GSD22 which has more power and improved networking

Garmin GSD-20 Fishfinder Module

The GSD 20 is a remote, black-box sounder that transmits 500 watts at 50/200kHz. It’s designed for use with the GPSMAP® 3006C, GPSMAP® 3010C, GPSMAP® 2006/2006C, GPSMAP 2010/2010C, GPSMAP 182/182C, GPSMAP 172/172C and GPSMAP 232 to provide SONAR capabilities to these units. The sounder module sends data serially in a Garmin proprietary format to up to two units on board. When viewed on Garmin chartplotters, you’ll see full-featured sounder displays in either split- or full-screen presentations. Features include auto-ranging, 2X and 4X auto and manual zoom, optional fish symbols and See-Thru® technology, which separates fish from thermoclines and structure.

Please Note: This product does not include a transducer. The transducer is sold separately.

Great for dual-helm boats; allows you to view and control sonar on one or two chartplotters

External mounting to allow shorter transducer cable length on large boats

4,000 watts transmit power peak-to-peak (500 watts RMS) 1,500 foot max depth*

Dual frequency 50/200 kHz (40/10) for shallow or deep-water performance

Display options — auto ranging, 2X and 4X auto and manual zoom, 3 fish symbol sizes, adjustment bar

Alarms — deep water, shallow water, 3 size fish, low battery

Transducer auto sense — automatically displays speed and temperature data without menus

See-Thru® technology — shows weak/strong returns simultaneously

Depth Control Gain (DCG®) — automatically adjusts fishfinder sensitivity according to depth

Size — just 4.75" W x 6.75" L x 2" H

Waterproof to IPX-7 standards

Easy installation

Comes standard with a 30-foot cable and mounting kit

Numerous transducer options including transom, plastic or bronze thru-hull, speed and temperature sensor