Casio Men's STB-1000-1CF OmniSync Sports Gear Bluetooth Fitness Smartwatch Smartphone links with only iPhone 5s/5c/5/4s (with iOS8 to 9.1), iPhone 6/6 Plus (with iOS 8.1.3 to 9.1), iPhone 6s/6s Plus (with iOS 9 to 9.1) Approximate 2-year battery life Features 1/100 second stopwatch, elapsed time, lap time, split time memory capacity: up to 120 records Water resistant to 330 feet (100 M): suitable for snorkeling, as well as swimming, but not diving