this version is suitable for WASH PUMP connection adjustable flow rate from 0 to 5 cc polypropylene + FV body pressure min 0.3 bar - max 3 bar spring-loaded ram in stainless steel The system operates by water pressure differential. During each cycle, the positive pressure on the outside causes rinse aid detergent to be sucked. at the end of every washing or rinsing cycle, a spring injects the desired quantity of liquid in the rinsing tubing.