This set contains ten 5 1/4" square geomorphic dungeon level pieces and five 2 1/2" X 10 1/2" additional dungeon level pieces which are semi-geomorphic.
From the introduction:
This set of geomorphs will provide you with an endless number of combinations with which to create your D&D "Underworld" -- be it one dungeon or many. Your geomorphs can be combined to form levels of all sizes, Huge or just a single piece.
Included is a sample dungeon layout with room descriptions and dungeon creation advice.