3″D x 36″l, pellet vent pipe, fully unitized, twist lock construction, can be used in both vertical & horizontal installations, 3-5/8″ od, designed for stoves that burn wood pellets, double wall & air insulated pipe, inner wall of 012″ super ferritic stainless steel, outer wall 018″ laser welded galvalume, patent pending venting for stoves & inserts that use wood pellets, UL listed for 3″ clearance to combustibles in USA & Canada.