Finally, a GPS-enabled training device that isn't afraid of the water. The rugged Forerunner 310XT is the triathlete's indispensable training tool - a GPS-enabled trainer that is water-resistant to 164 ft (50 m), tracks data in multiple sport modes and sends it wirelessly to your computer. This multisport device has up to 20 hours of battery life, tracks distance, pace and heart rate¹ on land, and goes from wrist to bike in seconds.The Forerunner 310XT times your swim in the pool or the lake. And while the GPS signal does not track distance while swimming like it does on land, thanks to a recent software update, it now accurately estimates open water swim distance and average speed. Simply enable the Swim mode and press start as you begin your swim. When finished, press the lap button and the 310XT automatically processes a combination of the time and GPS data to compute an estimate of distance covered and average speed while swimming.When you're ready to jump out of the water and onto the bike, Forerunner 310XT moves easily from wrist to bike with the optional quick release and bike mounts, making the transition between sports effortless. Forerunner 310XT categorizes multisport activities in one workout and also can log transition time in the process, so you can analyze your performance from start to finish.