It measures roughly eight metres east to west and five metres north to south, rising to a maximum height of about 0.7 metres at its eastern end. At its northern edge, a single upright stone with a rounded crest, aligned east to west and standing half a metre tall, adds an oddly deliberate note to what might otherwise be mistaken for a natural feature.

This is a fulacht fia, a type of prehistoric cooking site found in great numbers across Ireland. The typical interpretation is that animal hides or wooden troughs were filled with water, which was then heated by dropping fire-cracked stones into it; those stones, once spent, were piled to the side, gradually forming the horseshoe-shaped or oval mounds that survive today. The Rinnamona example sits in notably good company. A second fulacht fia lies approximately twelve metres to the southeast, and at one point three further examples were recorded around 150 metres to the north, though that cluster later came into question. Closer investigation suggested the locational data had been distorted during a transfer between mapping scales, and a gravel bank measuring roughly nine metres long and three metres wide, sitting about thirty metres to the north, may have been misread as one of those additional sites. It is a useful reminder that the prehistoric record is always in some degree of conversation with the practical difficulties of recording it.

What remains clear is that this small corner of County Clare attracted repeated use over time. The proximity of water, whether from the turlough itself or from sources now altered or lost, would have been essential to the function of any fulacht fia, and the clustering of several such sites in a relatively tight area suggests this was a place people returned to, rather than one visited only once.