The PR-500SS Prime rite stainless steel automatic pressure drop activated trap primer valve will prime up to 2 floors drains with our patented distribution DU-U or DU-4 units. System operating range is 20 psi minimum to 80 psi (138 to 552 kpa) maximum. The valve requires a 10 psi (70 kpa) pressure drop across the valve to activate and will deliver a metered amount of water to the floor drain. Trap primer is to be connected to a cold water supply only. Constructed of 316 stainless steel, EPDM E70 O-rings, Dow #7 Silicone, #60 stainless steel mesh screen, stainless steel piston.