Radium Injector Seats for Top Feed Conversion Fuel RailsThese are the same machined aluminum injector seats used in Radium fuel rail kits. They are required when converting an OEM side feed injector to a top feed injector that uses a 14mm lower O ring. They simply "pop" into the intake manifold (1 required per injector). They seal to the machined injector counterbore using the included Viton O ring. The 2 sizes are based on the intake manifold's inside diameter of each injector counterbore. Below are just