3" PelletVent PRO, Attic Insulation Shield.
This is a 3" Attic Insulation Shield, this is from the PelletVent Pro Line. It has the duralock tightening system, to get a tight fit. This is required for installations that pass through an attic to prevent insulation and debris from accumulating near the vent. This will give you a 1" Clearance to combustibles.