Each of the metals used to make Apple Watch (first-generation) is a custom alloy, engineered to be both beautiful and durable. Apple Watch Sport (first-generation) features anodized aluminum cases with a silver, space gray, gold, or rose gold finish. Apple Watch (first-generation) models are crafted from stainless steel or space black stainless steel. Each case is available in two sizes: 38mm and 42mm. There~s also a wide range of interchangeable bands made from a variety of materials. Apple Watch (first-generation) has breakthrough technologies like the Digital Crown, Taptic Engine, and Force Touch. And with up to 18 hours of battery life, you can use it all day long.**Requires iPhone 5 or later.