Timex Ironman Midsize Road Trainer Heart Rate Monitor Watch Target Zones, Averager Heart Rate, Time in Zone Calories Burned, % of Max Heart Rate Display, Recovery Heart Rate Timer, Max Heart Rate Zone Calculation Digital Transmission, Data Recorder 2 and Data Recorder compatible 100-hour chronograph with lap and split, either in large digits. 50-lap memory with ave heart rate per lap. 100-hour, 2-mode countdown timer 100m water resistant, Owner-Replaceable Battery, INDIGLO night-light with the press of any button using NIGHT-MODE feature