The PoolMate2 is an automatic Swimming Computer. Simply press the Start button and begin to swim. No forgetting your lap count No pressing buttons at the end of each lap Now you can concentrate on your stroke or switch off and relax. Join the thousands of PoolMate users and make the most of your swim sessions with this special watch.NEW FEATUREA simple calibration lap is all that’s required to set up the special open water mode, which uses the in- built accelerometer to work out the swim metrics. Using this method rather than GPS, which takes a lot of power and has difficulties operating in water, means the PoolMate2 has a battery life of over 2 years How does it work?The open water mode is a swim pedometer. Swim a lap of a known distance first and follow the calibration instructions then the watch will use this information for subsequent open water swims. Recalibrate regularly for best results.Features: Works with all major strokes straight out of the box, no calibration required Stores over 100 sessions for recall, records individual sets and total session data Pools over 18m (yards too), Chrono mode for other sports Water resistant to 50m, 24 hour clock and alarm Spec: Battery life around 24 months CR2025 Weight 41g Diameter of face 40mm Strap fits wrists from 14.5 to 21.5cm 12 month guarantee This watch calculates and shows: Laps Average strokes Speed Distance Time Calories Efficiency About SwimovateSwimovate are the market leaders and have been selling PoolMate watches for over 3 years all over the world. Before they launched, the PoolMate had been extensively tested by a wide variety of swimmers over a 2 year period. They have a database of hundreds of kms of swimming and an accuracy rate of over 99.75%. There are tens of thousands of PoolMates being worn everyday and helping swimmers all over the world. The watch has full CE and FCC approvals. Patents and trademarks granted. As long as you have a regular stroke and take more than 7 strokes per lap (on the arm the watch is worn on) you should have accurate results.