If you're looking for a Handheld GPS, look no further than Garmin! The best and only handheld GPS units we recommend for marine use are made by Garmin. Important features that will vary between the models based on what is important to you. Do you need something that floats, has an altimeter, utilizes topographic or marine maps, or just something that will allow you to track back your route with waypoints? The most popular marine handhelds from Garmin are the GPS Map 78 series.