The T-Rex is an outdoor smartwatch with military certified specs, and is ideal for sports/fitness enthusiasts and for those who love adventure. The rugged T-Rex thrives in harsh environments and unpredictable conditions withstanding extreme temperature (-40 to 70 ° C), damp conditions, salty environments It’s also packed with multi-sport mode, a 1.3-inch clear AMOLED screen, GPS, PPG BioTracker, HRM, activity and sleep monitors. What’s more — you get upto 20 days of battery life! in.amazfit.com