DuraVent Round Type B Gas Vent Model BV 3" - 4" Appliance Increaser o21 Strategically placed holes in the

Strategically placed holes in the double-wall structure draw in air from the bottom and feed the heated oxygen to the top

Must be field ovalized

HE38 Air Space on Sides No Brand Heatilator

DirectVent Pro Collection 5" x 8" Inner Diameter Galvanized Ceiling Firestop

DuraVent Round Type B Gas Vent Model BV 3" - 4" Appliance Increaser o21 Strategically placed holes in theOur non positional lock system on the Duravent BV Gas Vent is the best lock system on the market today. The incorporation of the DuraTab feature simply improves our lock system by adding flexibility and meeting market needs. The BV line of Duravent round vent pipe and fittings is designed for use on approved gas appliances in residential and light commercial and industrial applications. What's Included (1) Appliance Increaser Features Use to increase