Tracks heart rate and calories burned in real time through Wahoo"s proprietary algorithm * iPhone and iPad Compatibility - the Blue HR connects wirelessly via Bluetooth Smart (4.0) to your iPhone 4S and 5, 5C, 5S and iPad 3rd and 4th generations * Comfortable chest strap is waterproof and minimizes chafing * Works with the most popular running, cycling and fitness Apps such as Runmeter, RunKeeper, Cyclemeter, Strava, MapMyRun, Endomondo, Runtastic, Wahoo Fitness (included) and dozens more * Replaceable coin cell battery lasts up to 12 months