An enviro filter or air filter was a device designed to allow wearers to breathe normally in environments that would be otherwise dangerous. Some filters were sealed, with an integrated oxygen supply, to allow the wearer to breathe in the absence of an environment. The bounty hunter Mist had a sealed enviro filter as part of her suit of armor, with a three hour supply of oxygen; the helmets of many armor sets had air filters. They were a standard part of starships and space stations, and even some heavily-urbanized worlds such as Coruscant. Servicing of the air filters was part of a standard maintenance package.