The Apple Watch Series 7 45mm Sports Band features the largest, most advanced display yet. It comes with an always-On Retina LTPO OLED display, 1,000 nits brightness. The display is Crack Resistant, Dust Resistant (IP6X), and Swimproof with WR50 water resistance. Series 7 puts more health insights in sight. You can measure your blood oxygen level with a revolutionary sensor and app. Apple Watch Series 7 is capable of generating an ECG similar to a single-lead electrocardiogram. Along with other innovations like mindfulness and sleep tracking to keep you healthy from head to toe.  It can help you understand how well your body is absorbing oxygen and the amount of oxygen delivered to your body with the Blood Oxygen app. The entire charging system for Apple Watch Series 7 has been rethought to get you up and running faster than ever. With an updated charging architecture and fast-charging USB-C cable, it takes about 45 minutes to go from 0 to 80% charge. The Apple Watch Series 7 comes with no warranty.