American Metal Products 7.1-in x 1-ft 28 Gauge Galvanized steel Duct pipe

Strong durable galvanized steel outer pipe has internal spacing beads to assure a uniform insulating air space between pipe walls. Venting for type BW gas appliance installations. Oval pipe and fittings is designed for in-the-wall construction. Selkirk gas vent pipe and fittings have been tested and listed per UL 441 for installations as type B and B-W gas vents to be installed in single and multi-story buildings in accordance with the stands of the national fire protection association.