5in. to 6in. Single Wall Black Stove Pipe Increaser/Reducer Our Single Wall Stove Pipe Increaser / Reducer is made with .030 cold-rolled, heavy gauge steel Superior pipe on the market due to it's thickness; 60% thicker than most brands 100% Laser Advanced Resistance Welded Seams creates a round pipe to pipe fit every time Installation support before and after the sale; we're here to help you do it yourself Use Single Wall Stove Pipe Increaser / Reducer with vertical pipe and minimum of 18 in. clearance to combustibles