Apple Watch Series 8 features advanced health sensors and apps, so you can take an ECG¹, measure heart rate¹ and blood oxygen², and track temperature changes³ for advanced insights into your menstrual cycle⁴. And with Crash Detection, sleep stages tracking, and advanced workout metrics, it helps you stay active, healthy, safe, and connected. See Dimension section below for band sizing information. | Refurbished Excellent | | Apple Watch Series 8 (GPS) 45mm Aluminum Case with Sport Band | M/L | | 2022) | Midnight | Best Buy