Incorporating Fumotos most compact ball valve, Fumotos FN series valves are designed to fit cars, light trucks, vans and select commercial engines. These models are equipped with a nipple which allows a hose to be attached for convenient draining. Constructed of forged brass and stainless steel to exacting Japanese specifications, the FN series valves are designed to provide a lifetime of dependable and reliable service. The size of engine oil drain valve is NPT 3/8 - 18. Used to drain engine oil with the touch of a finger and eliminates stripped threads. It replaces drain plug for quick, easy, clean oil change. It is also ideal for drawing small sample of oil for oil analysis. Helps to avoid contact with hot oil and prevents hands and clothes from getting messed up. NOTE: The FN series are NOT RECOMMENDED for engines with low ground clearance.