Barberi® check valves are monodirectional devices, allowing the backflow prevention of fluid under pressure. According to the model, they are normally used in domestic water installations, booster pump systems, heating systems, central heating systems, heat generators (wall-mounted boilers, solid fuel generators, heat pumps), generic industrial and agricultural water systems. Sealing is permitted through forces exerted by a spring and by the fluid pressure against a gasket which guarantees the seal even at very low back pressures. Moreover, the force of the spring allows the valve to have a universal characteristics concerning the installation position. The peculiarity of this valve is the compactness that allows its installation even in little spaces.