It measures roughly 1.57 metres by 0.6 metres and carries a small Latin cross carved in low relief, the kind of early medieval marker that once served as a grave slab or boundary stone within a monastic precinct. Its very plainness is what makes it easy to miss.

The slab sits in notable company. On one side lies a bullaun stone, a boulder with one or more artificial cup-shaped hollows ground into its surface, which were associated throughout early Christian Ireland with ritual use, cursing, or healing depending on local tradition. On the other side rests a further slab. Harold Leask, the architectural historian who catalogued much of Ireland's early ecclesiastical stonework in the mid-twentieth century, recorded this particular piece in 1950, placing it at the north-west corner of the church and describing it simply as rough-cut, with a small Latin cross in relief. Robert Cochrane had documented it earlier still, producing measured drawings that appeared in the Eightieth Annual Report of the Commissioners of Public Works in Ireland, published in 1925 as part of his detailed record of the ecclesiastical remains at Glendalough.

When visiting, it is worth knowing that the slab was largely grass-covered as recently as 2005, so locating it requires a deliberate look along the northern flank of St Kevin's Church rather than a casual glance. The cross itself is in low relief rather than incised, meaning the carving sits slightly proud of the stone surface, which can make it harder to read except in raking light.