Float Operated Valves controls the liquid level and prevent overfilling tanks. The valve is operated mechanically by a float which rests on top of the liquid. The liquid level rises, it pushes the float up and closes the valve. The valve opens when the level falls. The amount of liquid pressure is determined by the length of the rod and size of the float. It includes dual inlet thread for connecting pipe and locknut and high tensile serrated arms. It is provided with the rise of a float prevented by the elastic force of a spring mounted on the valve body. It provides a safe and effective means of venting fuel, oil or water tanks without liquid loss.