Pressure suit
A pressure suit is an environmental suit worn when atmospheric pressure gets too low or too high to be survivable without. The minimum survivable pressure corresponds with an altitude of 15,000 meters above the surface of Earth, where the pressure dips to 102 millibars. Pressure suits must thus be worn by pilots who fly at high altitudes, unless the cabin of the airplane is pressurized. There's partial pressure suits and full pressure suits spacesuits are examples of the latter.