Irregular in shape and modest in size, measuring just 43 centimetres high and 40 centimetres at its widest, it is the kind of object easily passed over, yet its surface is carefully composed: a single-line Latin cross set within a single-line frame, the upper portion wheeled, and the spandrels, the triangular spaces between the arms of the cross and the enclosing frame, filled with angular lines. At the head, the base, and the end of each arm of the cross sits a small circle with a deliberate central depression, punched or incised into the stone.

Inishcaltra, known in Irish as Inis Cealtra, is a monastic island in Lough Derg on the River Shannon, associated from an early period with St. Caimin, who is said to have founded a community there in the seventh century. The church in which the slab now sits bears his name. Cross-slabs of this kind are among the most common markers of early medieval Irish ecclesiastical sites; they served as grave markers or devotional objects, and their designs range from simple incised lines to elaborate interlace. This particular example was recorded by the archaeologist R. A. S. Macalister, who catalogued it in 1916 to 1917 as number 83 in his survey of the island's carved stones, and a measured drawing was later made by de Paor. The combination of the wheeled head, the framed cross, and the circled terminals with their central depressions places it within a recognisable early Christian tradition, though the angular decoration in the spandrels gives it a slightly individual character.