This is a small round cairn crowning the ridge overlooking the massive Carn Saith-wraig to the northwest. It is itself easily overlooked, but this would be a shame if you happen to be visiting the latter, since a nearby quartzite stone (and potential additional cairn) hint at a mini-prehistoric complex here.
A compendium of DAT (PRN 8528) reckons:
“A small round cairn on the highest point of a broad ridge at 461m above OD. The site consists of a rough platform of large stones....
[with] a diameter of c.8m and a height of 0.4m.... The cairn is intervisible with standing stone 9117 and another possible prehistoric cairn, 9118, to the S and SW of this site respectively. The site enjoys extensive views out down the Doethie valley and over to the Brecon Beacons.”