5" X 4" Type B Gas Vent Reduction Tee 5GVTR4 5" X 4" Type B Gas Vent Reduction Tee attaches smaller pipe to branch and larger pipe to body. Use for a90 ° offset or to combine connectors from two or more appliances into a common vent. Branch swivels for alignment. Diameters: 5" x 4" Branch swivels for alignment Sturdy metal construction .010†Double-wall aluminum flex inner wall (two-ply .005â€) .018†galvalume outer wall with twist-lock connections.