I have to admit I had my doubts about this device. I figured it was just a gimmick that would be fun to play with but had no real fishing application. Boy was I wrong. When Eric Granstrom and I tested it we were amazed. It took Eric a couple of minutes to download the free app and we were viewing an incredible display. The unit turns itself on when it makes contact with the water and instantly begins sending the same kind of screen that you would see on the fish finder in your boat. It gives you depth and water temperature, and has a range of 120 feet. You can program depth, fish and low battery alarms. The batter charges with USB attachments that come with the unit. There are too many features to list here. I would suggest that you see Gary at Bob Feil Boats and Motors in East Wenatchee and have him show you all that this unit can do. I am going to take one of these along with me to fish from shore at Lake Roosevelt for trout this winter. I will know what depth the water I am casting my bait into, and even see if there are fish there. I will also use it for ice fishing. Just drop it in the hole and it will tell me if there are perch or trout down there. You really have to see this unit work to appreciate what it can do for you. It is a game changer for those who fish from shore or on the ice.