... to the workers, who work in the different filed, such as industry, the agriculture, the scientific organization and so on, and need to touch the ... valve, harness. The harness can be adjusted according to the users’ needs.2. Technical Standards2.1 Cartridge (3#) life time ≥ 45 min. ... piece, the user should leave the area at once and change a new one. The air tightness of the half face piece needs to be ...