SIZE FIRST - Diesel Ultrahuman Ring sizes are different from standard ring sizes. Purchase the Sizing Kit first to find your perfect fit available in 10 sizes from 5-14.- FORM & FUNCTION FULLY IN SYNC - Diesels iconic style meets Ultrahuman's precision health technology in this limited edition smart ring for those who carry their power and flaunt it like a bold statement. The Double-D design paired with intelligent insights makes this more than a smart ring: its fashion of the future.- COMFORT FOR THE EVERYDAY - Forged with space-grade Titanium, the Diesel Ultrahuman Ring is built to last yet features a comfortable form factor. The inner shell is made of hypoallergenic material which effortlessly houses 6-Axis Motion Sensor, a PPG (Photoplethysmography) Sensor, and a medical-grade Temperature Sensor all without compromising on how it pairs with your wardrobe.- AN EXTENSION OF YOU - The Diesel Ultrahuman Ring brings pure performance to meet your personality. Phantom (Distressed Black) embodies an elusive and gritty presence industrial at heart, refined in form. Cryo (Shiny Silver) reflects the integration of protocols in the bleeding edge of health and fashion icy in tone, effortless in presence.- ADVANCED SLEEP INSIGHTS - Diesel Ultrahuman Ring is the perfect form factor to track your sleep. With insights on all your sleep stages REM, Deep Sleep, Light Sleep and Wakefulness get actionable steps to improve sleep so you're ready for the day.