I see several similar product-description pages that refer to the reinforced strip/side as the binding edge. I suggest punched binding edge. This, of course, is the edge that goes into the loose-leaf binder.

I see several similar product-description pages that refer to the reinforced strip/side as the binding edge. I suggest punched binding edge. This, of course, is the edge that goes into a loose-leaf binder.

Each binding edge is 11-hole punched to ensure they are compatible for any binder or presentation cover. Google Shopping