Use the Wahoo Fitness Tickr Heart Rate Monitor in conjunction with most popular running apps, or use Wahoo's own running app to maximize your performance. . ANT and Bluetooth enabled, connects to both smartphones and GPS watches to track your heart rate and calories burned in real time. Two LED lights show the devices connection and heart rate detection. Tracks heart rate and calories burned in real time. Compatible with over 50 iPhone apps including Runkeeper, Strava, MapMyFitness, and CyclemeterRunmeter. Wahoo Fitness Burn and Burst Heart Rate Training Program designed to burn fat and improve performance is available for free within the Wahoo Fitness App. Works with iPhone 4S and newer, also with select androids. Replaceable coin cell battery lasts up to twelve months.