Apple Watch Series 6 lets you measure your blood oxygen level with a revolutionary new sensor and app. Take an ECG from your wrist. See your fitness metrics on the enhanced Always-On Retina display, now 2.5x brighter outdoors when your wrist is down. Set a bedtime routine and track your sleep. And reply to calls and messages straight from your wrist. It’s the ultimate device for a healthier, more active, more connected life. Originally released September 2020 S6 SiP with 64-bit dual-core processor Electrical heart sensor (ECG app)¹ Water resistant to 50 metres² Always-On Retina LTPO OLED display (1,000 nits brightness) 802.11b/g/n 2.4GHz and 5GHz Bluetooth 5.0 Built-in rechargeable lithium-ion battery (up to 18 hours³>) Third-generation optical heart sensor Accelerometer: up to 32 g-forces with fall detection Gyroscope Ambient light sensor Capacity 32GB Ceramic and sapphire crystal back