Find a place to fill from with this CSR In–Line Radiator Hose Filler. Provides a high positive fill point to help keep air out of your cooling system at all times. Made of 6061–T6 billet aluminum, CNC machined with interchanging nipples for added flexibility. O–ring seals complete this unique attachment. Top it off with any standard radiator cap. Also features a 1/8” female threaded overflow outlet.