An enviro filter, alternatively known as an air filter, was engineered as a mechanism enabling individuals to respire naturally within surroundings that would otherwise pose a threat. Certain filters were constructed as sealed units, incorporating an internal oxygen source, thereby permitting respiration even when an atmosphere was absent. The bounty hunter known as Mist utilized a sealed enviro filter, integrated into her armored suit, which provided a three-hour oxygen reserve; furthermore, air filters were often a standard component of various armor helmets. These filters were commonly found on starships and space stations, and were even prevalent on densely populated planets like Coruscant. The routine upkeep of these air filters was a component of standard maintenance procedures.