1. Pilot-oriented mode:optional for internal or external;
2. Structure in sliding column mode:good tightness and sensitive reaction;
3. Double control solenoid valves have memory function;
4. Internal hole adopts special processing technology which has little attrition friction,low start pressure and long service life;
5. No need to add oil for lubrication;
6. Affiliated manual devices are equipped to facilitate installation and debugging;
7. Several standard voltage grades are optional.