Design and Build: Military-Grade Toughness The Amazfit T-Rex Ultra doesn’t just look rugged—it’s engineered to survive extreme conditions. Constructed from polymer fiber with a reinforced metal frame, it meets 15 MIL-STD-810H military standards. This includes resistance to thermal shocks (-40°C to 70°C), 100-meter water pressure, humidity, and corrosive salt spray. The rotating crown is shielded