This valve has been designed for use on cylinders for reversible ploughs to obtain the automatic oil flow reversal, and therefore the reversal of the hydraulic cylinder which rotates the plough. As well as a double pilot operated check valve it is provided with a maximum relief valve which reduces the pressure of cylinder extension (head side pressure) in order to protect the mechanical stops and the plough’s structure. The reversal of the cylinder is controlled by a pressure compensated relief valve set to exactly in the dead head point of the plough, generating more power and speed. It can be assembled on heavy and unbalanced ploughs with cylinders with the following internal diameters: 40/50, 60/80, 80/100, 100/110, 110/130 mm.