1. Dual valve design, sequential system.the HKS super sequential blow-off (SSQV)is a dual stage pull-type relief valve, which will not leak under any level of boost. 2. This ensures a quick valve response and complete closure idle. 3. Pull-type blow off valves will work for any turbocharged vehicle, from stock to highly tuned. 4. The SSQV will operate under any boost pressure setting without leaking.