Thru-The-Wall, 3"- 4", Type L Pellet Kit, Vent System For Pellet Stove Applications, Includes One 4" Horizontal Cap, One 4" 90 Degree Elbow, One 4" Wall Bracket, Five 4" x 1 Pipe Lengths, One 4" Tee With Cleanout, One 4" Wall Thimble, One 4" Tee Support, One 3" To 4" Pellet Increaser & One 3" Pipe Connector.