Garmin GPS MAP176C 3.8-Inch Waterproof Marine GPS and Chartplotter

Works great and easy to use.

Although the 176C is not intended to be used in cold weather, and on a snowmobile, it does quite well. I have one rubber mounted behind the windshield, and have it wired to sled power. For really cold weather, I made a bonnet to go around the GPS, and wired in a heating element from a handgrip warmer to keep it from freezing. This does quite well until the temp drops to about -30 degrees farenheit.The display is very readable in direct sunlight. In lower light conditions, I just leave the backlight on high, and you can see it just fine. The marine mount that comes with the unit is plenty sturdy enough for use on the sled. There is nothing like being able to check your position without stopping (just don't do it while riding in a wooded area). When you do stop to take a break, the quick disconnect of the marine mount makes it easy to remove it. Also, you will want to use lithium batteries in cold weather, as alkalines do not work in the cold.