The stone measures 1.9 metres long and roughly 0.4 by 0.3 metres in cross-section, and along one of its angles runs a line of ogham, the early medieval script that encodes letters as a series of notches and strokes cut along a central ridge or edge. Someone, at some point, had decided this inscribed standing stone was more useful as structural material than as a monument.

The stone was one of six ogham stones recovered from a souterrain, an artificially constructed underground passage typically associated with a ringfort and used for storage or refuge, at Knockshanawee in County Cork. The six stones had been recycled as lintels spanning the roof of the souterrain, which itself lay within a ringfort. This particular stone served as the seventh lintel. Its inscription has been examined by successive scholars: Power in 1932, Macalister in 1945, and McManus in 2004, each reading the principal text as BRANI MAQQi Mu[C]C..., a personal name followed by a patronymic formula meaning roughly "of the son of", the standard ogham commemorative structure. Macalister also detected additional scores further along the right-hand angle, tentatively reading them as R[A]L, though the damage and weathering leave those letters uncertain. The name Bran, from which BRANI is a genitive form, appears elsewhere in early Irish records and suggests a date somewhere in the early medieval period, though the stone's reuse in the souterrain means it had already been displaced from its original context long before anyone thought to read it again.