Duravent 3" PelletVent Pro 3" Wall Thimble with 3" Air Intake, #3CAS-WTPK

This is a replacement combustion air system wall thimble for DuraVent PelletVent Pro 3" venting with a painted black exterior. This wall thimble measures 9" x 14 3/4" and will fit wall depths from 4" to 6 1/2" and includes an insulation ring to reduce air infiltration where the pipe slides through the thimble.Combustion Air System is a patent-pending design that pre-heats combustion air. Inbound air is circulated through baffles around the heated areas of the wall thimble pre-warming the combustion air before it is delivered to your stove