HEV Mark IV

The HEV Suit,[1] or Hazardous EnVironment suit, often called the "Hazard Suit" for convenience, is a full-body hazardous materials suit developed at the Black Mesa Research Facility. Designed for Black Mesa scientists to protect themselves from radiation, energy discharges, blunt-force trauma during the handling of hazardous materials, and the effects of traveling to Xen as part of Survey Teams. It is predominantly worn by Gordon Freeman during much of the Half-Life series - first as the Mark IV suit in Half-Life, then as the upgraded Mark V suit in Half-Life 2. It allows him to sustain many injuries from damage that would normally fatally wound him, such as projectiles or melee attacks. The HEV Suit is related to both the Powered Combat Vest (PCV) used by the Hazardous Environment Combat Unit (HECU), and the armored vest and helmet used by the Black Mesa Security Force.