Apple Watch S3 38mm. Whether you’re looking to track your fitness, stream music, or find your phone, the Apple Watch S3 38mm has it all. It is customizable with an array of interchangeable bands making it perfect for any occasion. The Apple Watch S3 38mm also comes with: a second-generation retina OLED display; GPS; a S3 SiP with a dual-core processor; a W2 wireless chip; an optical heart sensor; emergency SOS; a built-in speaker; WiFi and Bluetooth; an 8GB capacity; and is water resistant up to 50 meters.