During the early empire, among soldiers it was common to attach 4-8 leather straps hanging down at the military belt. When the soldiers were sitting, this apron avoids deeper insights underneath the tunika, and it was highly decorated as a status symbol.
This apron stiffener plate is not enameled, but the triangles are blackened. Example of a complete apron is shown in pic. 2.The plate can be attached with mushroom-shaped buttons at the backside, no rivets needed. Also available as raw piece with 20% discount.