HKS Super SQV (Sequential Blow Off Valve) uses a unique sequential valve structure and a differential pressure control system, which allows for a broad operating range from low boost to high boost. Its Pull-Type relief design ensures stable operation regardless of the amount of boost pressure. Super SQV changes driving experience of turbo charged vehicle and improves engine response. Factory recirculation valve sound is so quiet it can be barelly noticed, HKS Super SQV IV has a unique & sharp sound. It significantly improves driving experience and looks great in the engine room as well. HKS also offers an environmentally friendly recirculation tube - suction return.