Still one of the most secure ways to fasten something, buckles were once used for much more than simply holding pants up. From Latin buccula (cheek strap) the buckle first came into widespread use by the Roman Legions to fasten their helmets into place. Throughout the ages the simple buckle has been indispensable for fastening armor, adjusting sword belts and baldrics, or holding down the boxed lid of a mercenary companys pay coffer.
The length measurement has been taken along the horizontal axis of the buckle or along the flat edge of a D-ring buckle. Fits a 5/8” inch wide belt or strip of leather.