Not only does the New Pool Mate 2 gives you speed and distance in the pool, it now does it in open water too Swimovate's has also boosted the battery life for the Pool Mate 2, which now has a crystal glass face and larger clearer display.In the poolCounts laps, strokes, distance, speed, efficiency, duration, sets, rest time and caloriesIn open waterCounts strokes, distance, speed, efficiency, duration, sets, rest time and caloriesA 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 Out of the waterA 99 set chrono mode for timing• Stores 50 sessions for recall, records individual sets and total session data• Pools over 18m (yards too)• Water resistant to 50m, 24 hour clock and alarmSpecBattery life around 24 months CR2025Weight 41gDiameter of face 40mmStrap fits wrists from 14.5 to 21.5cmCrystal glass face, PU strap, stainless steel back12 month guaranteeHow does it work?The PoolMate2 contains MEMS accelerometers (first used by NASA) to capture the motion of your arms. The software times your swim and calculates lap count, average strokes, speed, calories and efficiency levels so you can work on improving your technique.AccuracyWe are the market leaders and have been selling our PoolMate watches for over 5 years all over the world. Before we launched, the Pool Mate 2 had been extensively tested by a wide variety of swimmers over a 2 year period. We have a database of hundreds of kms of swimming and an accuracy rate of over 99.75%. There are tens of thousands of Pool Mates 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.