Used to ensure clearance to combustibles is maintained. Also serves as a firestop. Adjusts from 4-1/8″ to 7″ to fit thickness of wall. Type B gas vent. No. 187703: Wall Thickness: 4-1/8 In. – 7 In., Size: 3 In., A Size: 3-5/8 In., B Size: 7 In., Material: Galvanized Steel, Temperature Rating: 550 F, Grade: UL Listed, Pkg Qty: 1 No. 187704: Wall Thickness: 4-1/8 In. – 7 In., Size: 4 In., A Size: 4-5/8 In., B Size: 8-1/4 In., Material: Galvanized Steel, Temperature Rating: 550 F, Grade: UL Listed, Pkg Qty: 1 No. 187705: Wall Thickness: 4-1/8 In. – 7 In., Size: 5 In., A Size: 5-5/8 In., B Size: 9-1/2 In., Material: Galvanized Steel, Temperature Rating: 550 F, Grade: UL Listed, Pkg Qty: 1 No. 187706: Wall Thickness: 4-1/8 In. – 7 In., Size: 6 In., A Size: 6-5/8 In., B Size: 10-3/4 In., Material: Galvanized Steel, Temperature Rating: 550 F, Grade: UL Listed, Pkg Qty: 1
