DuraVent DuraVent Attic Insulation Shield, 3" - 4" Type B Round Gas Vent

DuraVent Attic Insulation Shield, 3 inch - 4 inch, Type B Round Gas VentRequired for installations that pass through an attic to prevent insulation and debris from accumulating near the vent.Cylindrical section adjusts from 11" to 20"Inside diameter of cylindrical section is 6-3/4 inchesOutsie diameter of cylindrical section is 7-3/16 inchesBase Plate is 9-1/4 inches squareA product from DuraVent's Type B Gas Vent system. Use with natural gas or liquid propane category I and drafthood equipped appliances...