... installed on hydraulic valve for AUTO-OPEN-CLOSE This brass made 3 way valve has 3 positions to select ... different control loop, normally it marks AUTO-OPEN-CLOSE. The main port ... is 1/4" (male) as inlet, which can pass water, oil, gas, etc. The other 3 ... pressure is 10 bar.Basically, this valve is for hydraulic valve to select functions like pressure reducing, ...