This 3 Inch x 6 Inch Pellet Chimney Straight Black Length Pipe from the PelletVent Pro series is a Type L Biofuel Chimney Pipe component and consists of the duralock system for a tight seal. Features fully unitized, twist-lock construction in 3 and 4 diameters. Listed at 1 clearance to combustibles in the USA and Canada. It can be used in both vertical and horizontal installations. Stainless steel welded seam inner wall, combined with a galvalume welded seam outer wall. Pipe OD is diameter plus 5/8 . Galvalume or painted black outer finish. 12 length available with stainless steel outer SS . To calculate installed length, subtract 1 1/2 from each length of pipe. Features Type Chimney Straight Pipe. Finish Black. Pipe Class Type L. Pipe Shape Round. Series PelletVent Pro. Outer Pipe Material Galvalume. Vent Construction Double Wall. Fuel Type Biofuels, Oil, Wood Pellet. Inner Pipe Material 444 Stainless Steel. Perfect Fit Construction Allows Ease Of Twist-Lock Connections. Specifications Overall Dimensions 6 L . Inner Pipe Gauge 30. Outer Pipe Gauge 28. Pipe Inside Diameter 3 .