Display 45mm 396 by 484 pixels 1143 sq mm display area; 41mm 352 by 430 pixels 904 sq mm display area; Always-On Retina LTPO OLED display Apple Watch Series 7, Apple Watch SE, and Apple Watch Series 3 have a water resistance rating of 50 meters under ISO standard 22810:2010. This means that they may be used AlwaysOn Retina display Up to 2,000 nits. S9 SiP. Double tap gesture. Faster on-device Siri. Precision Finding for iPhone. Blood Oxygen app 10. ECG app 11. High and low heart Apple Watch Ultra 2, Apple Watch Series 9 and Apple Watch SE require iPhone Xs or later with iOS 17 or later. Thelargest display, with up to 3000 nits of brightness — the brightest display Apple has ever designed. Large enough to see up to six lines of workout metrics at a glance. Readable even in direct sunlight. Always-On technology keeps the display on so you can see key information at a glance. The new exclusive Modular Ultra watch face is MQO1.