7" To 8" DuraVent DuraBlack Increaser 7DBK-X8 This increaser is used to increase from a smaller appliance flue outlet (7") to a larger diameter chimney or stove pipe (8"). Measures 7" long. 24-gauge strength Lock seams 18" clearance to combustibles Painted black Single-wall interior stove pipe for connecting wood stoves to manufactured chimney Economical and drip-free connection No need for cutting or crimping