Get rid of that uncomfortable chest strap and run, cycle, swim and train with Mio's Alpha 2 Heart Rate Sport Watch. Optical Heart Rate Technology equips this watch with a sensor that tracks your heart rate with peak precision whether you're training on land or underwater. There are configurable heart rate zones with multi colored LED lights to indicate which zone you're beating in. This watch also records your pace, distance, and calories, and there's a memory for up to 25 hours. Bluetooth Smart connectivity lets you transfer your workout data to Mio's GO app or your favorite smartphone applications to further your fitness. The USB rechargeable battery has a long life in between charges.