This nozzle is designed to mount in the deck or cowl of your racecar connected to your overflow hose from your radiator to give you an early warning of your system pressure. When your water pressure exceeds your radiator cap it will allow the water to flow through this nozzle. We designed the nozzle to have the least amount of drag making it the most aerodynamic overflow nozzle on the market today. The nozzle also comes with an aluminum nut and O-ring to lock it securely in place.