Apple Watch Series 2
The Apple Watch Series 1 and Apple Watch Series 2 are the second-generation models of the Apple Watch. They use SIPs (System in Package), the Apple S1P and Apple S2 respectively, and the Series 2 has a built-in quick-on GPS and twice the display brightness of the previous generation for easier outdoor readability. The Apple Watch Series 1 and 2 require an iPhone 5 or later on iOS 10 or later.

Features 
Apple Watch Series 2 has a water resistance rating of 50 meters. It can keep track of the number of laps and distance during Swimming workouts. During swimming, the touch function can be manually disabled with 'Underwater mode'. Once this is turned off, by rotating the Digital Crown continuously, it uses the speaker to expel residual water through a series of 10 vibrations. The Apple Watch Series 2 has a built-in GPS system. The most recently used apps are saved in the background, so apps and information load faster. The Apple Watch Series 2 was sold in both matte Aluminium, starting at $369, and polished Stainless Steel, starting at $549, while the Series 1 was sold only in Aluminium, starting at $269. The Series 2 still needs to be charged nightly, with an advertised 18 hours of battery life, in line with its predecessors. The display is also brighter, from 450 nits to 1000.

Software 
The Apple Watch Series 2 was first released with watchOS 3 preinstalled and is still compatible today with the newest version, watchOS 6.1.

Confusion 
The Series 1 and Series 2 watches were released at the same time. Both the Series 1 and 2 have faster processors than the first-generation model, but the Series 2 also has waterproofing, allows for swimming workouts, and has a 1000-nit display. With the exception of the faster processor, the Series 1 makes no changes to the first-generation. The first-generation Apple Watch is commonly called the Series 0 by the surrounding communities, but Apple itself doesn't use this name, instead referring to the Series 0 as "Apple Watch (1st generation)".