It measures roughly eight centimetres in height and twelve and a half centimetres wide, with barely a centimetre of its thickness visible above the surrounding masonry. What makes it worth pausing over is what covers its exposed face: an incised text, fragmentary and incomplete, taking up most of the surviving surface. Whatever the inscription once said, only a portion of it remains, and the original form of the slab itself is no longer known.

The stone is catalogued by scholars Elisabeth Okasha and Katherine Forsyth in their 2001 study of early medieval inscriptions, where it appears as Toureen Peacaun 21. Okasha and Forsyth describe it plainly as a fragment of a slab of unknown form, which is itself a quietly significant phrase: this is not a stone whose purpose or shape can be reconstructed with any confidence. Inscribed slabs of this kind are associated with early Christian monastic and funerary traditions in Ireland, sometimes marking graves, sometimes commemorating individuals by name, sometimes serving liturgical or devotional functions. Without more of the text, and without more of the stone, those possibilities remain open. The church into which it has been absorbed, St Peakaun's, is itself a site of considerable age, and the slab's incorporation into the wall fabric suggests it was already a fragment, its original context lost, by the time someone decided it was useful as building material.