Sapphire crystal display on stainless steel cases
GPS models
S8 SiP with 64-bit dual-core processor
W3 wireless chip
U1 chip (Ultra Wideband) footnote1
Digital Crown with haptic feedback
Accelerometer
Up to 256 g-forces with Fall Detection and Crash Detection
High-dynamic-range gyroscope
Temperature sensing
Blood oxygen sensor and app
Electrical heart sensor and ECG app
Third-generation optical heart sensor
High and low heart rate notifications
Irregular rhythm notification
Emergency SOS
Crash Detection
Fall Detection
Water resistant 50 metres
Dust resistant (IP6X)
Crack-resistant front crystal
Wi-Fi 
Bluetooth 5.0
GPS/GNSS/GLONASS/BeiDou
Compass
Always-on altimeter
Built-in speaker and mic
32GB capacity
Fast charge
Dimensions
Height: 41mm
Width: 35mm
Depth: 10.7mm
Weight: Aluminium 31.9g (GPS)
Weight: Aluminium 32.2g (GPS + Cellular)
Height: 45mm
Width: 38mm
Depth: 10.7mm
Weight: Aluminium 38.8g (GPS)
Weight: Aluminium 39.1g (GPS + Cellular)