The DuraPlus 6" - 8" Class A Chimney Pipe Storm Collar is required with DuraPlus flashing to create a weather proof penetration through the roof deck. Seal inner edge of the collar to the chimney pipe with non-hardening 500 Deg F high-temperature sealant. Features: Type: Storm Collar. Required with DuraPlus Flashing. For use with 6"-8" DuraPlus Class A Chimney Pipe. Seal Collar Edge to Chimney Pipe with Non-Hardening 500 Deg F High-Temperature Sealant. Specifications: Inner Diameter: 10"-12".