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. It has been designed to control two cylinders on plughs with the rotation of the frame upwards (see scheme). Operation: the two cylinders work in parallel. Fist cylinder B starts lining up the load (as it requires less pressure). Before the end of stroke, cylinder A starts the overturning. Once the dead head point (90°) has passed, the cylinders A and B restart together taking the plugh back to its working position.