Air Operation Type Valve requires a controller to operate the Motor,

 but Air Type can only operate with Air without requiring a controller.

When you put air in the open side, the flapper opens 90º Open, and in this state,

 use a micrometer to close until the desired vacuum pressure is generated.

In other words, if you put air on the open side, the flapper becomes full open, and if you put air on the close side, the flapper moves at a setting angle momentarily.