The WHOOP Strap collects physiological data 24/7 to provide the most accurate and granular understanding of your body. It's lightweight, waterproof, and features the new and improved 5-day battery life and BLE connect. Optimize the way you recover, train, and sleep with daily reporting on mobile and desktop apps. Know how hard to work with the all new Strain Coach. Discover how much sleep you actually need and how you can align it to your circadian rhythm using the Sleep Coach. WHOOP is the first system to automatically track your body’s unique physiological state to determine your personal readiness to perform each day. WHOOP tells you exactly how much sleep you need each night in order to reach your peak performance.