Manufactured with a large 0.69" internal bore, the fuel rail can support all necessary engine power requirements. They are CNC machined from extruded 6063 aluminum, media blasted, black anodized, and laser etched for a high quality surface finish. Like the OEM fuel rails, the injector bores are 14mm ID so factory injectors are permitted. The fuel rail is equipped with features to accept the OEM fuel injector clips This kit is compatible with all fuel types including popular alcohol mixtures such as E85. The OEM insulating spacers (Honda P/N: 16638-PNA-000) are reused and washers are included to thermally insulate the fuel rail from the aluminum intake manifold. The fuel rail ports are tapped for 8AN ORB. Fittings ARE NOT included with the fuel rail and must be purchased separately. Appropriate fittings must be selected based on the specific application. Ample space around the fuel rail port(s) is necessary for larger accessories such as fuel pressure regulators, fuel pressure gauges, and fuel pulse dampers. To verify clearance, the dimensional drawings on the product pages can be used as a reference guide. This fuel rail is compatible with all OEM Honda K-series intake manifolds (RBC, RBB, RRC, PRB, etc). If using an aftermarket manifold (Skunk2, etc) check with the manufacturer about fuel rail compatibility. If the manifold fits the OEM fuel rail, then the Radium fuel rail will also fit.