SpeedFactory Racing Honda/Acura H-Series Upper Coolant Fill Neck - 32mm - SF-06-066Whether you have a custom radiator or a SpeedFactory Race Tucked radiator, you need a proper way to fill your engine's cooling system from the highest point and we have the solution. SpeedFactory Racing H Series Upper Coolant Fill Necks are compatible with most aftermarket radiator setups, and change the high point of your cooling system for easy filling and system air bleeding. Our necks are manufactured in house using high quality aluminum materials