M&G DuraVent 0070 3GVl45 3" Adjustable Type-B 45 Degree Elbow. DuraVent has incorporated a new and innovative system that features a lock-tight connection for Type B natural gas and propane vent applications. This Type-B Gas Elbow is designed to withstand the rugged demands of continuous gas ventilation in residential and industrial applications. This Adjustable 45 Degree Elbow also comes equipped with an inner wall that is engineered to heat up rapidly, and remain hot during operation of the appliance which increases ventilation and appliance efficacy. The M&G DuraVent 0070 3GVl45 3" Adjustable Type-B 45 Degree Elbow features deep locking grooves for a quick and secure lock, a corrosion resistant galvanized body, aluminum inner wall, and hand adjustable areas. These adjustable areas can be hand-spun into a straight extension piece or an offset 45 degree elbow. The M&G DuraVent 0070 3GVl45 3" Adjustable Type-B 45 Degree Elbow is not compatible for coal or wood-burning applications.