If your application does not include a Return Kit, then it is designed to vent to atmosphere. However, HKS vent to atmosphere BOVs can be converted to recirculate with minor modifications. If you are purchasing the Universal application, please choose the other appropriate adapters and flanges for your custom setup. Most application specific kits come with HKSs Triple Fin VTA inserts. Some vehicle specific kits also come with additional pipes or mounting hardware. The SSQV4 is the latest iteration of HKSs pioneering sequential blow off valve. Using all the engineering expertise learned in the first 18 years of the super sequential line, the SSQV4 is the best blow off valve for your turbocharged Import. Utilizing a nickel plated secondary valve and stainless steel internal hardware to react quickly, even under low boost conditions, and still seal completely in high boost applications. Dont forget the distinctive staggered sound that has been the calling card of HKS Super Sequential Valve equipped Imports. The SSQV4 uses the same mounting and external dimensions as the previous HKS Blow Off or Recirculating Valves, enabling direct fitment replacement of older HKS designs.