Product Details: Heart rate Workout smarter. Track your intensity level with streaming real-time heart rate with the soft-strap chest belt. Training zones Stay in the zone. Set the customizable heart rate zones and know when you need to push yourself a little harder. Calories Burned Get a better calorie burn estimates during your exercise routine when you track your continuous heart rate. Stopwatch Track your total workout time with the 100-hour stopwatch1/100 second resolution No Recharging Wear it anytime and anywhere without recharging. Long battery life with a standard coin cell battery.