Its purpose was specific and unglamorous: it served as a place to prepare or manage horses during the process of loading them with seaweed, known locally as straddling, before the animals carried their loads inland to fertilise the thin soils of the Aran Islands.

The structure is modest by any measure. Rectangular in plan and built in drystone, a technique in which stones are fitted together without mortar, it measures just 3.7 metres long and 2.6 metres wide, with its entrance facing east. What lifts it slightly above the ordinary is the corbelling that survives in the north-west corner. Corbelling is a building method in which courses of stone are laid so that each projects a little further inward than the one below, gradually closing the gap to form a rough roof or internal shelf without the need for timber or mortar. That this detail survives at all in so small and functional a building suggests it was constructed with some care. Tim Robinson, whose meticulous geographical and cultural survey of the Aran Islands recorded the site in 1980, noted its connection to the seaweed-gathering tradition that was, for centuries, central to the island's agricultural survival. Seaweed, or feamainn, was the primary means by which islanders built up the soil on Inis Mór's bare limestone, and the logistics of transporting it on horseback were part of the annual rhythm of life there.