The castle itself is a nineteenth-century structure, but the plaque is considerably older, and has been set into a later moulded surround as though the builders, or someone after them, recognised it as something worth preserving and displaying rather than discarding.

The carving is done in raised relief and follows the conventions of heraldic display: a chief indented, a bendlet sinister, and five escallops. These are the broadly decorative elements, but it is the row of objects beneath them that catches the eye of anyone familiar with Irish noble genealogy. Where the Butler family arms typically show three covered cups, this shield shows only two covered cups and a jug, a subtle but deliberate variation. Above the shield, the name "Edmonde Butlere" is carved, with the opening letter E executed in an elaborate interlace style that suggests a craftsman with some pride in the work. The base of the shield has suffered minor damage, but the carving is otherwise legible. The Edmond Butler named here may be Edmond Butler of Rathbrit, identified as the second son of John Butler of Derryluskan, who was himself the second son of James, ninth Baron of Dunboyne. If the identification is correct, this Edmond was dead by 1600, placing the plaque firmly in the late sixteenth century and making it a fragment of the older Gaelic and Anglo-Norman world that the nineteenth-century castle was built over or around.

The plaque sits in plain view on the turret face, visible from the front of the building, so no special access is required to see it. The heraldic detail rewards a close look, particularly the interlace work on the capital E and the small distinction in the cup arrangement that separates this shield from the more standardised Butler arms.