The STM Evo X fuel rail fitting bolts to the stock or an upgraded aftermarket fuel rail with factory style outlet. Our fitting has a -6AN ORB outlet to allow for an aftermarket fuel pressure regulator to be installed.CNC machined in-house and hard anodized black, safe for use with gas, E85 and race fuels. Includes stainless hardware that sits flush with the fitting for a clean install and utilizes an oring for a leak-proof connection to your fuel rail.