This part is required for installing some espresso machines, such as La Marzocco (Marzocco part #L032/P.01), and is placed in-line on the outward flow water fitting from a rotary vane pump. Also referred to as a “check” valve. For use in-line in the hydraulics of CMA equipment (Astoria, Bravo, Formula, Rio and Wega), use part W_225, or AS_232
