The inner aperture of this coining collar shows a blank area between areas where reeding has been machined into the collar wall. This createsthe edge of a struck piece using this collar in a coining press. It will have a plane edge where the blank area without reeding is located and two areas with. Note lettering on the collar indicatesthis is for a 50mm (2-inch ) coin, dual blank areas - called "bars" here -- and the date it was made. Any number of blank with reeded areas is called interrupted reeding. Photo Medallic ArtCompany.