Polar H7 Bluetooth Heart Rate Sensor & Fitness Tracker HEART RATE MONITOR: Provides live, accurate heart rate to compatible mobile training apps through Bluetooth Smart technology FITNESS TRACKER: Waterproof heart rate sensor, Compatible with iPhone 4S, iPhone 5, iPod touch (5th generation), iPad (3rd and 4th generation), iPad mini and iPod Nano (7th generation)Bluetooth Smart transmission technology STRONG BATTERY LIFE: For optimal battery life, detach transmitter from chest strap after every use ADVANCED TECHNOLOGY: Gym Link connects Polar heart rate monitors and activity trackers with compatible gym equipment CALORIE COUNTER CAPABILITIES: For those who want to count the calories they burn and get basic heart rate-based features to keep their fitness training simple