The Ultrahuman Ring AIR is the lightest sleep tracking ring, designed to provide comprehensive insights into your sleep, activity, and recovery. It tracks sleep stages (REM, Deep, Light, Wakefulness) and offers actionable steps to improve sleep quality. The 'Movement Index' monitors daily activity, steps, workouts, and calories to optimize glucose metabolism and increase non-exercise energy usage. Dedicated workout mode tracks heart rate for fitness insights. Enhanced recovery tracking includes a 'Dynamic Recovery Score' based on heart rate, HRV, and skin temperature, updating in real-time with naps or sauna sessions. Forged with space-grade titanium and a carbon coating, it offers enhanced comfort and durability with a minimal form factor. The Ring AIR boasts a 6-day battery life and charges in just 90 minutes. It also discreetly monitors heart rhythm for early signs of AFib, provides habit-building reminders for Vitamin D and caffeine intake, and tracks menstrual cycles with fertility insights. Size is crucial; purchase the Ultrahuman Sizing Kit first to ensure a perfect fit. No subscription is required; all insights are available through the Ultrahuman app.