It now forms part of the altar itself, built into the southern end of the altar's front face, where it sits flush with the masonry as though it always belonged there.

The slab, roughly 90 centimetres tall and just 26 centimetres wide, carries an incised ringed Latin cross, the kind of early Christian carving found across Ireland from roughly the sixth century onwards, in which a circle intersects the arms of the cross to form a distinctive ring. Here, the arms are slightly expanded and open-ended, meaning they flare gently outward and do not close into solid terminals, and they extend a little beyond the ring rather than stopping at it. Above the head of the cross, the design terminates in a small roundel. The shaft, however, is incomplete; a break in the slab has taken away part of it, so the full original composition can only be partly reconstructed. Scholars including Manning and Higgins have catalogued it among the cross-slabs of the region, identifying it as Slab C within the Teaghlach Éinne grouping.

Teaghlach Éinne, meaning roughly the household or familia of Éinne, refers to the monastic enclosure associated with St Enda, the founder credited with establishing one of Ireland's earliest and most influential monasteries on Inis Mór, traditionally dated to the late fifth or early sixth century. The site itself contains a scatter of early grave-slabs, and this one's incorporation into the altar structure gives it an unusual dual status: it is simultaneously a liturgical object and an archaeological artefact, still in situ but in a context that was almost certainly not its original one.