Garmin Fishfinder 120 4.5-Inch Waterproof Fishfinder with Sounder Offers one of the largest and highest resolution displays of any fishfinder in its class Internal backup system saves your settings in power outages See-Thru technology identifies fish returns under the toughest conditions, and Depth Controlled Gain automatically adjusts fishfinder sensitivity according to depth Built to withstand submersion in up to three feet of water for up to 30 minutes Alarms indicate deep or shallow water, fish, and low battery