It is narrow, only about eighty centimetres wide internally, and just under four metres long, with walls nearly two feet thick and standing to a height of roughly a metre and a third. Built into the hillside and open at the north-east end, it has the look of something purposeful rather than incidental, though precisely what purpose that was remains unclear.

Drystone construction, which uses carefully fitted stones without mortar, was practised in Ireland across an enormous span of time, from prehistoric field walls and early medieval enclosures right through to post-medieval shelters and agricultural outbuildings. The dimensions here are notably confined, too narrow for comfortable habitation, which might suggest a shelter for an animal, a storage cell, or possibly something connected with seasonal activity on the mountain. The Galty range, one of the longest inland mountain chains in Ireland, was used for summer grazing, and small structures associated with that transhumance tradition are not unusual at altitude. Some collapse is visible in the interior, particularly from the south-east wall and the rear, so the full original form is difficult to read on the ground.