The DuraTech 7 Class A Chimney Pipe Attic Insulation Shield is required for installations that pass through an attic to prevent insulation and debris from accumulating near the chimney.Fits over Firestop Radiation Shield or a support box Consists of two parts – a collar and a base Adjustable lengthADA Compliant: No Collection: DuraTech Fuel Type: Coal, Gas, Oil, Wood Height: 15 Inner Diameter: 7 Material: Galvanized Steel Outer Diameter: 9 Pipe Class: Class A Pipe Shape: Round Style: Functional Vent Construction: Double Wall Weight: 7