SELKIRK CORP 184600 Gas Termination Kit, 4-Inch 4" inch, 4RV-TK, 4 Piece, Round, Type B Gas Vent Termination Kit includes top flashing, storm collar and draft hood connector Constructed from galvanized steel, which resists corrosion Type B gas vent kit for gas appliances in residential and light commercial and industrial applications Outer pipe has internal spacing bends, to assure a uniform insulating air space between pipe walls