The Garmin GNX 21 is a 4" inverted-display marine instrument built around a first-of-its-kind glass-bonded hybrid LCD that combines directly driven segments with a dot-matrix field. High-contrast digits scale up to 36 mm tall, delivering sharp readability from full sunlight to total darkness, while its NMEA 2000 connectivity surfaces 50-plus vessel parameters — including GPS speed, water depth and temperature, and wind direction and speed — at a glance. Low power draw makes it especially well-suited to sailboats that need reliable data without heavy battery demand.

Specifications:

• Display type: Inverted 4" glass-bonded LCD with anti-glare lens — white or color digits on a black background
• Digit height: Scalable up to 36 mm
• Backlight: 7 selectable colors plus custom color option
• Display configurations: 5 layouts (single, dual, triple function, gauge, and graph mode)
• Parameters supported: 50+ marine and boat parameters (depth, speed, wind direction, wind speed, GPS speed, water temperature, and more)
• User profiles: Fully customizable for sailboat or powerboat use
• Auto-scroll: Rotates through data pages at a user-set interval for hands-free operation
• Power consumption: 25 mA; 350 mW (no backlight) / 400 mW (mid-level backlight)
• Connectivity: NMEA 2000 (built-in); NMEA 0183 supported via optional 7-pin bare-wire power/data cable
• Mounting: Included low-profile flush mount; optional flat mount available separately

In the Box:

• GNX 21 instrument
• Trim piece snap cover
• Protective cover
• Flush mount gasket and hardware
• NMEA 2000 T-connector
• NMEA 2000 drop cable
• Installation instructions
• Documentation

Note: This product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns.