AmeriVent 4E4 Type B Gas Vent Pipe, 4 in OD, 4 ft L, Galvanized Steel (Pack of 6)

The Type B designation is assigned to gas venting systems that meet the safety requirements of Underwriters Laboratories, Inc. The Amerivent all-metal, double-wall gas vent is listed as Type B by Underwriters Laboratories, Inc. and is approved for such residential and commercial applications as Category 1 water heaters, boilers, furnaces, space heaters or wall heaters. UL-approved Type B gas vent products form a continuous passageway from an approved gas appliance to the termination of the vent above the roof of the structure.