304 Stainless Steel Manifold Header Reducer Pipe 3mm 2-1.75 Inch 2.00-1.75" O.D. 304 Stainless Steel Reducer Pipe, Polished Finishing (no coating, can be welded without any issue) These are heavy duty Extruded SS Tube 3mm (11 Gauge) Thick Won't Crack, can be welded to make many custom Manifolds, headers for Extreme High Power applications.