ARI started production of the RP-500 Series Reduce Pressure Zone assembly in 2007. The RP-500 assembly is made from composite plastic material, resistant to corrosion, scaling, fertilizers, herbicides, insecticides etc.  The ARI RP-500 is known as an anti-theft backflow device due to design of the body being completely made of composite plastic.  The newer RP-500 design now comes with new composite inlet and outlet shut off valves.