The pool is modest, just 1.6 metres across, fed by a natural spring and edged with coursed stonework. At its western side, a lintelled channel carries the water away. On the gravelled bottom, modern coins lie scattered around a small slate slab, roughly the size of a paperback book, into which a cross has been incised. A cement cross standing to the east of the pool is inscribed with 'IHS' and the name of St Fursey. The well is also known by two Irish names, Tobar na hAbha Cumhra and Glaise Chumhra, the fragrant stream, and it is from this name that Knocknadobar itself is said to derive.

The well is dedicated to St Fursey and is associated with the cure of eye complaints, a tradition rooted in the story of the saint's own blindness. Folklore collected from An Clochar School in Cahersiveen describes Fursey travelling along the mountain with only a dog as his guide when he felt water beneath his feet. He stooped, washed his face, and saw daylight for the first time. The account closes with the observation that, since the saint was born blind, the well's curative properties are properly the concern of blind people alone. The well's main occasion was the last Sunday of July, when it served as the starting point for a Lughnasa assembly on the summit of Knocknadobar. Lughnasa, the ancient Celtic harvest festival associated with the god Lugh, was marked here with singing, dancing, and games, making it as much a communal celebration as an act of devotion. In 1885, Stations of the Cross were erected along the route from the well to the mountaintop, formally integrating the holy well into Catholic devotional practice while the older pattern of festive gathering persisted alongside it.