It is the kind of object that would be easy to walk past without a second glance, yet the east face of the slab carries at least seven cupmarks, shallow circular depressions ground into the stone surface by human hands, probably thousands of years ago.

Cupmarks are among the most widespread yet least understood forms of prehistoric rock art found across Ireland and Britain. They are made by a pecking or grinding technique, leaving bowl-shaped hollows in the rock surface, and while they appear throughout the Bronze Age record, their precise purpose remains a matter of debate among archaeologists. The Balteen example is a relatively modest specimen: the slab measures about 1.1 metres long and 0.9 metres high, and is only around 10 centimetres thick. The cupmarks are concentrated on the upper half of the east face, each reaching up to about 10 centimetres in diameter and 4 centimetres in depth. At some point the stone was incorporated into a roadside field boundary on the western side of a road on a south-facing slope, a fate common to many prehistoric carved stones in rural Ireland, where ancient material was simply reused as convenient building material without any particular awareness of, or concern for, what it was.

The slab is reported to be obscured by briars, which means any close inspection would require care. Its incorporation into a working field boundary also means that much of the stone is effectively fixed in place and only the exposed east face is accessible to view.