GPSMAP 431 Chartplotter and 431s Chartplotter / Fishfinder

Features an ultra-bright 4" QVGA display along with an improved high-speed digital design for faster map drawing and panning speeds. Plus, these waterproof units have a high-sensitivity internal GPS receiver, so mariners will always know their position on the water. They are ready to go with built-in cartography for inland U.S. waters (over 14,000 lakes) and Garmin's proven easy-to-use interface designed to help you navigate the waters with ease. 

Features and Specifications:

• Ultra-bright 4" diagonal QVGA display, 240 x 320 pixels - over 800 nits of brightness
• Preloaded with charts for over 14,000 U.S. lakes and navigable rivers
• Built-in high-sensitivity GPS receiver
• High-speed processor for fast screen redraws and smooth panning
• Streamlined user interface makes it simple to select modes and features
• Single SD memory card slot for BlueChart g2 Vision cards, as well as saving waypoints, routes and tracks to an SD card
• Optional BlueChart g2 Vision cards provide marine chart detail and enhanced navigation features like Auto Guidance, satellite imagery, 3-D Mariner's Eye View and 3-D Fish Eye View
• Backlit keypad for easy operation in low light conditions
• Unit dimensions: 5.0"H x 5.7"W x 2.7"D 
• Power output: 400 watts (RMS) 3200 watts (peak to peak), dual beam
• Depth: 900 feet/300 meters (dual beam)
• Use a dual frequency transducer 80 kHz (45 degrees), 200kHz (14 degrees) for maximum saltwater performance
• Patented transom/trolling mount transducer
• UltraScroll high rep rate sonar provides lightning-fast screen updates
• AutoGain technology enhances target visibility
• See-Thru technology shows weak and strong returns simultaneously
• Water temperature log graphically records water temp data
• A-scope
• Round flasher display mode
• Whiteline
• Adjustable depth line helps gauge desired fishing levels and bottom clearance
• Split zoom display offers a closer look at fish targets and bottom structure
• 2X, 4X, and bottomlock zoom
• Adjustable keel offset
• Alarms for fish size, shallow water, deep water, and low battery
• Add Sonar, GPSMAP 431s , comes with Dual Frequency Transducer that illustrates Depth Contours, Fish Targets and Structure.
• Owners Manual :   Download