Quality Garmin eTrex H waterproof GPS system, accurate down to the exact mile per hour.
* Handheld GPS navigator designed for outdoor enthusiasts
* High-sensitivity, WAAS-enabled 12-parallel-channel GPS receiver
* 500 user waypoints w/ names & graphic symbols; built-in patch antenna
* 4-level gray LCD display; automatic track log with 10 saved tracks
* Requires (2) AA batteries; measures 2 x 4.4 x 1.2 inches (W x H x D)
* The rating is IPX7, which means that it can be submerged into 1 meter of perfectly still water for 30 minutes.
Take caution when it comes in contact with moving water because the movement of water can exceed the pressure of 1 meter of still water, especially around the buttons.
Garmin recommends that if you are running in hard rains or if you are concerned about it "hitting" the water from a boat, keep it in a waterproof case.