DetailsHighlightsImportant! Size before buying: Purchase your Ring AIR sizing kit from Target first to get the perfect fit. Wear it overnight. Then return to Target.com to purchase the right size Ring AIR.The ultimate fusion in ring durability: The outer shell is made from Space-Grade Titanium reinforced with Tungsten Carbide Carbon coating, making it resistant to everyday wear and tear. The inner of the ring is coated with medical-grade hypoallergenic epoxy resin, making it comfortable to wear at all times.No subscription costs: No mandatory subscriptions needed to use the Ultrahuman Ring AIR and it's App with lifetime access to all data.Wake up to your sleep insights: The Sleep Index, intelligently designed to be your sole metric for sleep health, assesses your total sleep duration, resting heart rate, and restfulness, creating a comprehensive picture of your sleep quality.Temperature tracking: Skin temperature is vital for measuring your body's physiological states and responses to various factors, including exercise, stress, and illness.Dive deep, worry free: With water resistance up to 330 feet, revel in beachside frolic or dive into the pool. The Ring AIR is just as at home in water as it is on land.Stimulant window recommender: A game-changer for all caffeine enthusiasts, this capability helps you make smarter choices about your stimulant consumption. Break down your day into favorable times in which you can consume stimulants to enhance your productivity.Women's Health: Ring AIR comes with cutting-edge capabilities tailored for women's health, providing personalized insights into each phase of the menstrual cycle by correlating it with various biomarkers. Additionally, it offers pregnancy insights designed for expecting mothers, enabling them to seamlessly track their biomarkers' correlation with trimester progression through individually tailored scores.DescriptionThe Ultrahuman AIR Smart Ring is a sleek, comfortable smart ring that tracks your sleep, reco