Heart rate sensor, accelerometer, and gyroscope
Ambient light sensor
Direct fire speaker and microphone
Wi-Fi (802.11b/g/n 2.4GHz)
Up to 18 hours of battery life
Space Gray aluminum case | S2 dual-core processor | Built-in GPS | Ion-X glass | 2x brighter OLED Retina display with Force Touch (1000 nits)
Wi-Fi (802.11b/g/n 2.4GHz) | Bluetooth 4.0| watchOS 3 | Height: 42.5mm | Width: 36.4mm | Depth: 11.4mm | Case Weight: 34.2g
Requires an iPhone 5, 5c, 5s, SE, 6, 6 Plus, 6s, 6s Plus, 7, or 7 Plus and iOS 10 or later. | Band with 42mm case fits 140-210mm wrists.