Most personal GPS devices provide little coverage for snowmobilers, according to online GPS snowmobile map provider GPSSledmaps.com. The best GPS units for snowmobilers incorporate downloadable snowmobile map content listings. This means that quality handheld GPS units accepting downloadable content, such as Garmin, Magellan and Lowrance Electronics, work best, according to online adventure publication Off-Road Outdoors. Look for handheld GPS devices allowing for simple map uploading, and purchase maps covering areas of snowmobile use. Quality GPS snowmobile maps provide shelters, local roads and gas stations in addition to trail listings. GPSSledmaps.com even provides tools for creating personalized maps.