The ETS intercooler piping kit uses 2.5" OD 304 Stainless Steel tubing. The piping is 1 piece mandrel bent with no welds or joints to disrupt flow. The ends of the pipes are beaded so you won't have to worry about couplers coming off during a pull. We finish our pipes in a wrinkle black powder coat. We guarantee the best possible fitment which will save you precious time during install.