Rev9Power Rev9_AC-002; Adaptor Tube For Type-RS Blow-Off Valve(2.5 Inch Dia.) Product Details Aluminum blow off valve (BOV) adapter tube 2.5" fits all TYPE-RS blow off valves "- 2.5" piping size - 100% aluminum for easy intercooler piping welding - easily matches with the aluminum intercooler piping - light weight one-piece aluminum - polished look - beaded roll edge to prevent leakage