Aimed at the rapidly growing number of enthusiasts who prefer their performance accessories to be inconspicuous, the Sleeper Series is designed to blend into an engine bay without attracting any unwanted attention. Anodised in a super-smooth black, the Sleeper Series comprise of Blow-Off Valves, Boost Controllers and Waste Gates. The Supersonic BOV is best suited to high performance applications Purpose built to bolt on the WRX Maximum flow and maximum noise No adapters required Quick and easy fitment Adjustment via the unique Quick Wrist action (no spanners required) Supplied with a replacement flange gasket and blanking plug and all fitting hardware. Available in Blue, Polished, and Red.