Track your sleep, activity, and recovery trends to help you understand and improve your overall wellness Sleep Index evaluates your total sleep duration, resting heart rate, and restfulness to provide a complete overview of your sleep quality Skin temperature is crucial for tracking your body's response to factors like exercise, stress, and illness, offering insights into your overall physiological state Phase Response Curve (PRC) explains how stimuli like light, food, or exercise influence changes in your body's circadian rhythm Receive personalized insights and alerts that guide you to make healthier choices in real time Outer shell of the ring is crafted from fighter jet-grade titanium, reinforced with a tungsten carbide carbon coating for superior durability Interior is coated with medical-grade hypoallergenic epoxy resin, ensuring all-day comfort Ring size: 8