These watches link with the casio watches phone app to provide access to a number of functions that enhance your workouts.Daily health and fitness support functions include a 3-axis accelerometer that keeps track of your step count, a multi-timer that lets you create up to 20 timer combinations of five timers each, memory for up to 200 lap records, and more.The app also makes it possible to maintain step count logs with five exercise intensity levels, to calculate the calories you burn, to specify a daily step target, to create timer combinations and send them to the watch, to store stopwatch measurement data, to view data, and more.Other features include app-based auto time setting correction and other features for more efficient timekeeping, and an auto led light to facilitate workouts in areas where lighting is dim.Function: Fitness TrackerBattery Size: CR2025Proofs: Shock/Water ResistantBacklight: YesColor: Green