Vibrant Weld Flange Kit for HKS SSQ style Blow Off Valves AL Weld Fitting / AL Thread On FlangeVibrant Performance Weld On Flange Kit for HKS 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; 38. 2MM Overall H;