The new design, the double Viton O-Rings, and the high surface hardness billet aluminum that is used, allow for reliable operation over time without boost leaks in applications from 70 to 500hp, without any issues.   No check engine light or faults will be triggered, thanks to the second piston, which stops the air leakage in light engine loads and idling.   For engines equipped with a MAF sensor, it is recommended to use the double piston valve. The Kit includes: The Blow-off Valve Silicone Hose Stainless Clamps Black Silicone Vacuum Hose A Block off Cylinder for blocking the return hose if needed