DSB3 and DS5B Automatic Reversal Valve are directional valves with automatic inversion with hydraulic drive, for assembly on the plate. These valves invert the direction of the flow when the scope in one of the two users is nothing (for example, when a cylinder reaches the end of the race). The reversal process is independent of pressure in users. These valves are zinc-nichalate superficially, making them suitable for mobile and environmental applications (such as waste compactors) which require good protection from corrosion.