Top features: - Heart rate monitor to optimise your fitness training - Personal coaching app providing with feedback to help improve your performance - TwistLock Technology for secure and comfortable fit - Long-lasting battery life for sustained performance Heart rate monitor Keep track of your cardiovascular condition with accurate, vital and instant data. The JBL Under Armour Wireless Bluetooth Headphones give you on-demand heart rate updates so that you can stay on top of your fitness level and overall physical condition. Developed by experts and tested by athletes, the in-ear heart rate monitor is activated with a simple touch of your right earbud. Personal coaching app UA Wireless Bluetooth Headphones come with the UA Record app, which lets you track everything from workouts to steps and sleep. You'll get a free 12-month premium membership subscription to MapMyRun on purchase (subscription fees apply thereafter), letting you connect to keep track of your performance. TwistLock Technology Designed especially for demanding athletes, these wireless Bluetooth headphones feature sweat-proof ergonomic eartips that fit and stay in your ears so that you can concentrate on your health and performance. Long-lasting battery life With up to eight hours of battery lifer per charge, the JBL Under Armour Wireless Bluetooth Headphones let you plan nearly a week's worth of training.