The two small holes that allow the extension or 2+ together to screw on the nuts of the screws provided. If the holes could be wider on each side, this would the two small holes on each side are too close together and may be an issue. I’m unable to screw the nut on with any tool besides my fingers because the nut spacing is too close. So I imagine it’ll loosen overtime which could be a problem but currently my hand tightened nuts are working.
