Our 3/4″ diameter Low Pressure Airline Hoses specifically designed for our Cold Air System are NIOSH approved when used with the approved Allegro Supplied Air Respirators. Constructed from rugged clear polyvinyl chloride and reinforced with braided polyester textile yarn. These hoses provide a temperature range from -20° F to 150° F (-28. 8° C to 65. 5° C). Manufactured with Parker quick-connect couplers.