As we know, to the automatic swing door Operator, there are 2 type of arms, one is called pull arm /pull bar, the other is push arm which also called push bar,and do you know for which type of doors they will be used ? 

To the swing door, there are 2 directions,open inward and open outward. Considering the swing door Operator will be installed inside of the room in most of time, with this situation, if we want the door to open inward, the pull arm should be chose, and if we want the door to open outward, the push arm should be chose, to more details, please check the picture below for reference. 

Hope the words above will be helpful to you to choose the correct swing door operator .