PERRIN Boost Tube Kit Red Piping Black Couplers PERRIN boost tubes are CNC mandrel bent from aluminum tubing for better weight reduction. Every boost tube has an over sized beaded end to ensure the hose clamps and couplers stay connected and sealed! They choose to take the smoothest shortest path to get air to and from the intercooler. Tubes are available in a Black or Red wrinkle powder coat for a long lasting durable finish that looks good in any engine bay. Right off the turbo a smooth offset coupler carries the hot side air charge to a perfectly matched 2.25” boost tube. PERRIN chose 2.25" tubing for a smoother, cleaner, obstruction free routing while still being large enough to flow more WHP than most turbos can put out.