Premoflex is a quality non-gassing hose recommended for use with supplied air respirators. Non-gassing or outgassing refers to compressed air as it flows over the internal wall of the hose. A non-gassing hose will not introduce harmful vapors or gasses into the air stream. Moisture cannot wick through the walls of Premoflex hoses because of the high quality rubber composition liner. That makes Premoflex hose a great choice for air tools and spray guns as well as for supplied air breathing systems and spraying waterborne material. NIOSH approved.