AURA Strap 2 Activity Tracker for Apple Watch 41mm Coal Black NEW Authentic and Brand New! Includes: AURA Strap 2, Infinite Loops in M, L, XL and XXL, Coin Battery, Pick for Battery Replacement, Quickstart Guide Transforms your Apple Watch into the ultimate health tracker and helps you achieve your diet and fitness goals faster. Brings body composition and water level tracking right to your Apple Watch. Measure how much your fat, muscles, water level, and many more parameters change over the workout or diet process. Build the body of your dreams. Choose the body you want, and AURA App will help you build it. Get recommendations and precise analytics on your fitness journey to achieve results faster.