1.Stucture in sliding column mode:good tightness and sensitive reaction; 2.Three position solenoid valves have three kinds of central function for your choice; 3.Double control solenoid valves have memory function; 4.Internal hole adopts special processing technology which has little attrition friction,low star pressure and long service life; 5.No need to add oil for lubrication; 6.It is available to form integrated valve group with the base to save installation space; 7.Affiliated manual devices are equipped to facilitate installation and debugging; 8.Several standard voltage grades are optional.