Annovi Reverberi Gymatic 3B Unloader Valves with Injector. Pressure regulating unloader valve/control set which automatically relieves pressure from pump at shut-off. Pump pressure is reduced to zero but the line pressure is ‘trapped’ in the high pressure hose. 250 Bar maximum pressure. 1/2″ Male inlet x 3/8″ Male outlet. Built in by Pass and fixed or adjustable chemical injector models. Size 2. Annovi Reverberi Pump Series RR, XM, RK.