Apple Watch 42mm Stainless Steel Case (White Link Bracelet) Stainless steel case, Link Bracelet Sapphire crystal Retina display with Force Touch Ceramic back Digital Crown Heart rate sensor, accelerometer, and gyroscope Ambient light sensor Speaker and microphone Wi-Fi (802.11b/g/n 2.4GHz) Bluetooth 4.0 Up to 18 hours of battery life