Apple Watch Series 3 (GPS) requires an iPhone 5s or later with iOS 11 or later. Apple Watch Series 3 (GPS + Cellular) requires an iPhone 6 or later with iOS 11 or later. Apple Watch and iPhone service provider must be the same.
Product Dimension (Mm) : 42.5 (H) X 36.4 (W) X 11.4 (Depth)
Case Weight (Gps): 32.3G
Space Gray Aluminum Case
Built-In Gps and Glonass
Faster Dual-Core Processor