Apple Watch Series 3 GPS - 42mm - Sport Band - Aluminum Case Measure your workouts, from running and cycling to high-intensity interval training. Track and share your daily activity, and get the motivation you need to hit your goals. Better manage everyday stress and monitor your heart rate more effectively. Automatically sync your favorite playlists (1). And stay connected to the people and info you care about most.. GPS and a barometric altimeter track how far and high you go Dual-core processor for faster app performance (2) Ultimate sports watch and intelligent activity tracker Swimproof so you're always read for the pool or ocean (3) Alumninum case watchOS 4 is even more intuitive and intelligent 1. Apple Music requires a subscription 2. Compared with the previous generation 3. ISO standard 22810:2010. Appropriate for shallow-water activities like swimming. Submersion below shallow depth and high-velocity water activities not recommended