Not sure what they mean but these buckles suck. It's great that you can use it to get through airport security without removing your belt, but keeping your pants up is no compromise. I've already replaced the buckles with a worn and all metal version as the compression ports don't stay closed on them. The problem is that there is no insulation between the belt end and the belt face. This design needs rethinking. However, 2 stars for the quality of the belt itself. no abrasions. beautiful, thick and strong