Real-time heart rate monitor to track efficiency and performance Tracks BPM, average heart rate, max heart rate, and total calories Heart rate variability data available with a compatible app Lithium-ion battery lasts up to 100hr on one charge IPX7 water rating for sweatproof performance Handwashable strap fits up to 50-inch chests Supports iPhone, iPad, Mac, and Android devices ANT+ connectivity and up to three Bluetooth connections