DuraVent's innovative system for a lock-tight connection for Type B gas vent called DuraLock. See the alignment indicators meet, feel the ends grasp together, hear the snap as the connection firmly locks into place. DuraVent Type B gas vent is designed to meet the rugged demands of the job site. The inner wall is recessed to eliminate damage in handling. Type B gas vent has been engineered to heat up rapidly. It remains hot during the operation of the appliance with minimal condensation in the appliance and vent system. Type B gas vents are not suitable for use with wood burning or coal applications, industrial ovens, exhaust ranges and hoods, grease or pollution ducting, or as free-standing exhaust vents for high temperature applications.

• Use for venting listed natural gas or liquid propane category I, draft hood appliances or appliances that have been specifically tested and listed to use type B gas vent
• The appliances listed typically use type B gas vent systems, but not always - furnaces, water heaters, boilers, room heaters, decorative gas appliances and unit heaters
• Aluminum 0.012 in. inner wall