left hand or right hand opening

That's a question for the ages. Some manufacturers determine the hand from the outside view and some determine it from the inside view. Everyone has a different interpretation. Your best bet is to compare your part to our pictures on the 79-123 store page. The handing of the commercial door pivots we sell is determined from the outside view. The 79-123 pivot would be a left hand because the handle is on the left side of the door when viewing it from the outside of the building. That said, it's always best to compare physical attributes just to be 100% sure.