Timex Zone Trainer heart rate monitor helps you track your fitness level and progress. Display allows easy reading of continuous heart rate and elapsed time so you dont need to break stride. Automatic and manual training zones help you systematically condition your heart, helping you get and stay fit has visual in-zone indicator. Heart rate functions include after-workout recall of average, peak and minimum heart rates as well as recall of time in zone. On-the-chest monitor provides continuous heart rate readings during even the most intense activities. In addition to beats per minute, unit also displays percentage of max heart rate and tracks calories burned. One-minute and two-minute recovery rate timers let you determine how quickly your heart recovers after intense activity. Stopwatch features 27-workout memory recall and a 99-lap counter. Other watch functions include countdown timer, month/date, 12/24 hour time and three time zones. Uses digital transmission which eliminates cross-talk with other monitors and instruments. INDIGLO night light allows use in low-light conditions. Comfortable elastic strap is water-resistant to 99 feet 30 meters so you can use monitor in the rain not intended for underwater use. Watch is also water-resistant to 30 meters. CR 2032 3v batteries included in chest strap and wrist unit are replaceable by the consumer.