Apple 38MM SmallWatch Stainless Steel Case - Steel/Black Modern Buckle 1.5-inch AMOLED Capacitive Touchscreen, 340 x 272 pixels + Sapphire Crystal Glass Operating System: watchOS 2, Chipset: Apple S1, Processor: 520 MHz, GPU: PowerVR SGX543 Internal Memory: 8GB, 512MB RAM Heart Rate Sensor, Accelerometer, Gyroscope, Ambient Light Sensor Up to 18 Hours of All-Day Battery Life, Up to 3 hours Talk Time; About 1.5 hours to 80% Charge Time, About 2.5 hours to 100% Charge Time