A souterrain is a stone-lined tunnel, typically built during the early medieval period for storage or refuge, and whoever constructed this one had access to a remarkable collection of inscribed stones, seemingly indifferent to the writing on them, or at least more concerned with their dimensions than their meaning.

The stones came to wider attention in 1910, when the souterrain was discovered and the ogham slabs were retrieved. This particular stone, the third lintel, measures 3.1 metres in length and roughly 0.4 by 0.3 metres in cross-section. Its inscription has occupied scholars for decades, with some disagreement over the reading. Patrick Power, writing in 1932, rendered it as CUBBRIGAI MAQIMENU MAQ, followed by a damaged or illegible section. R. A. S. Macalister, whose 1945 corpus of ogham inscriptions remains a standard reference, and Damian McManus, writing in 2004, both read it slightly differently as CULRIGAI MAQI MENUMAQ[I]. The formula is characteristic of early ogham stones: a personal name followed by MAQI, meaning "son of", and then a second name, sometimes with a further generation appended. These stones served as grave markers or territorial declarations, their inscriptions identifying individuals within a lineage.

All six stones from Knockshanawee are now held at University College Cork, where they are on permanent display in the Stone Corridor. The collection there brings together ogham inscriptions from across Munster, and this stone sits among them with its partially legible name, still generating mild scholarly disagreement about exactly who it once commemorated.