Imperial Hazard Trooper

Imperial Hazard Troopers are a specialized type of soldier in the Imperial Stormtrooper Corps that are meant to serve in extreme environments. They wear a very heavy suit of body armor that offers complete immunity to temperature extremes, immunity to acidic damage, and a virtual invulnerability to small-arms fire. The armor is also a functioning space suit which can keep the wearer alive in a vacuum or underwater environment for up to three days. Hazard trooper armor is lightsaber resistant to a certain degree. Hazard Troopers differ from other stormtrooper units in that they are cyborgs and have their limbs removed and replaced with mechanical versions of them. They are commonly equipped with either an Imperial Heavy Repeater, Stouker Concussion Rifle, or a PLX-2M Portable Missile Launcher. =Sources=
 * Wookieepedia