Humminbird Fishfinder 581i HD DI Down Imaging GPS Combo: * Precision GPS technology and built-in UniMAP * GPS chartplotting and trackplotting * The Humminbird 581i DI Combo stores 2,500 waypoints, 50 routes, 50 tracks/20,000 points * Down Imaging Sonar provides photo-like views of the bottom * DualBeam Plus allows you to target both structure and fish * The Humminbird Fishfinder GPS Combo features a quick disconnect mounting system * Down imaging sonar returns a photo-like image below the boat * Backlit for night time use * The Humminbird Fishfinder GPS Combo has a waterproof construction * Temperature sensor * 2-1/2" target separation * 5" 640V x 320H 16-level grayscale display * Internal GPS receiver * Single, full-size SD card slot * Down Imaging 455/800 kHz, 75-degree/45-degree beam with 350" depth capability * DualBeam Plus 200/455 kHz, 28-degree/16-degree beam and 600" depth capability * 2400W peak-to-peak power * 2-year limited warranty * HD Down Imaging Marine GPS Fishfinder Model# 408990-1