The built-in, high-sensitivity GPS finds and maintains your position anywhere you go on the water. The GPS allows you to mark waypoints for different locations. So, if the fish are biting in 1 spot, you can mark it, and return to it on your next trip. Mark docks, boat ramps and other locations on the lake, and create routes back to them for your next trip. The STRIKER Plus 4 fishfinder makes fishing a breeze, and it's built to work in any environment.