Without cover. Designed to be re-used with the stock air cleaner cover for a true stealth high performance intake. Also allows installation of the Stealth ”optional air cleaner cover only”; which are available in multiple open or closed stylings. Backplate is made of advanced synthetic polymers; like used in high performance automotive manifolds and high-end handgun bodies. This material offers strength; thermal stability; chemical resistance and reduced heat transfer to intake components for best induction efficiency. Note: Compatible with S&S 558678 58mm throttle body.