Display: 1.5 "or 1.65"; Processor: Apple S3; Sensors: Accelerometer, altimeter (barometric altimeter), heart rate sensor, Bluetooth 4.2, NFC and GPS, ambient light sensor; Operating system: Apple watchOS Water resistant to a depth of 50 m 8 GB capacity Display: OLED ‑ display Retina second generation with Force Touch technology (1000 cd / m²), Ion-X glass Resolution: 272x340 pixels (38 mm model) and 312x390 pixels (42 mm model) Specification on the siteApple Description of the materials of the straps and watch case on the official websiteApple