Your essential companion for a healthy life is now even more powerful. Advanced sensors provide insights to help you better understand your health. New safety features can get you help when you need it. The bright, Always-On Retina display is easy to read, even when your wrist is down. The aluminum case is lightweight and made from 100 percent recycled aerospace-grade alloy. The Sport Band is made from a durable yet surprisingly soft high-performance fluoroelastomer with an innovative pin-and-tuck closure. Tougher than tough. It?s crack resistant, IP6X-certified dust resistant, and swimproof with WR50 water resistance. Also equipped with advanced health features such as temperature sensing is a breakthrough feature that provides deep insights into women?s health. Keep an eye on your blood oxygen. Take an ECG anytime. Get notifications if you have an irregular rhythm. And see how much time you spent in REM, Core, or Deep sleep with Sleep Stages.