The Ultrahuman Ring Air Smart Health-Tracking Gold Ring in size 8 is a stylish and advanced activity tracker designed for both indoor and outdoor use. Made of titanium and powered by batteries, this ring provides accurate tracking of heart rate, calories, and distance. It also features a variety of functionalities such as a clock, alarm, and sleep tracker. The ring is waterproof and comes with a wireless sensor for optical bio-tracking, making it ideal for gym training, swimming, and running. With a battery life of up to 6 days, this ring is compatible with both iOS and Android operating systems, and offers a sleek design in a luxurious gold color.