It is not particularly large, at roughly one and a half metres tall and less than two thirds of a metre wide, but its carved surface repays close attention. Cut into the face is a Latin cross with hollowed angles at the four junctions of the arms, each hollow filled with a small raised pellet, and a base that widens as it descends. The cross outline is formed by a broad, flat band rather than an incised line. What makes the slab especially arresting, however, is the inscription carved into the upper section of the stone: two horizontal lines of text that read, in Latin capitals, ORDODIARMAIT MACCDELBAID. The letters run upside down relative to the cross below them, a detail whose explanation has never been settled.

The slab was catalogued in the early twentieth century by R. A. S. Macalister, who placed its style in the twelfth century on the basis of the cross design, and later scholars Okasha and Forsyth examined both the carving and the inscription in detail. Cross-slabs are flat commemorative stones, common in early medieval Ireland, generally erected to mark a grave or to invoke a prayer for the person named. The name preserved here, Diarmait Mac Delbaid, is otherwise obscure, though the formula suggests this is a memorial or prayer inscription, with the opening word likely an abbreviated invocation. Inis Cealtra, a small island in Lough Derg on the Shannon, was an important monastic site associated with St. Caimin, and its graveyard contains numerous early medieval inscribed stones, making the island one of the more concentrated collections of such material in the country.

The island is accessible by boat from Mountshannon in County Clare, and the ruins of St. Caimin's church, along with several other early ecclesiastical remains, occupy much of the interior. The slab sits inside the nave, so reaching it involves entering the roofless but otherwise largely intact shell of the building. The upside-down orientation of the inscription is easy to overlook at first glance; it only becomes apparent when you try to read the lettering in relation to the cross beneath it.