Vibrant Weld Flange Kit for GreddyS/R/RS style Blow Off Valves AL Weld Fitting AL Thread On FlangeVibrant Performance Weld On Flange Kit for Greddy Blow Off Valves are made from your choice of 6061 Aluminum or Mild Steel construction. Each kit includes an O Ring for a leak free seal and also come with a radiused weld fitting that allows for a simple screw on of the matting flange; allowing for a convenient option to switch to a difference BOV down the road if you choose. Weld On Flange Kit; 2. 5 in. Coped For Tube OD; 35MM Port ID; For Greddy BOV;