The Ultrahuman Ring Air is designed for optimal sleep tracking, providing insights into REM, Deep Sleep, Light Sleep, and Wakefulness, with actionable steps to improve sleep. It also features a 'Movement Index' to encourage all-day activity for better glucose metabolism and increased non-exercise energy usage. The Ring AIR tracks steps, workouts, and calories, with a dedicated Workout Mode for monitoring heart rate during exercise. It also enhances recovery through its 'Dynamic Recovery Score,' which considers heart rate, Heart Rate Variability (HRV), and skin temperature. Forged with space-grade titanium, this sleek and comfortable smart ring offers precise performance. It does not require a subscription and is available in sizes 5-14. Purchase the Ultrahuman Sizing Kit first to ensure the perfect fit.