The Apple Watch Series 2 Aluminum 38mm was announced in 2016, September. Released 2016, December With 1.5 inches Retina OLED, 1000 nits (peak), Powered by Apple S2 (16 nm) and running watchOS 3.0, upgradable to 6.2.8, the device delivered smooth performance and multitasking capabilities. while the Li-Ion 273 mAh (1.03 Wh), non-removable ensured long-lasting usage.