The cave opens at the base of a long rock wall, in which there are other smaller openings. Its natural entrance (about 9 x 7 meters) is closed by a wall made of local stone and with a portal worked in Pietra del Finale. It consists of a first room rather large and high (10 x 18 meters) and a second more internal room of elliptical shape with a vaulted ceiling without concretions and with large collapsed rocks on the floor. The cave has not returned archaeological materials because the clay deposit has already been removed in the past. In the first part of the cave, dry and well lit, you can still see some traces of the ancient clay deposit on the walls. The closing wall was built in rather regular courses, with medium to small stones joined by clay. At about half of the wall there is the opening of the door framed by a portal in Finale Stone and jambs made of squared stones.
The architrave is made of a single stone; underneath both stones of the jambs have been chiselled in order to obtain a sort of arched decoration. Above the lintel in the masonry there is a lowered arch made of smaller stones and the space of the lunette, between the lintel and the arch, seems to have been plugged later. The door has a monolithic threshold.
The interior of the cave has no other masonry structures; however, we note the presence of a basin for the collection of water made out of a boulder.
It has not been possible to trace the origin of the two names attributed to this cave; it should be noted, however, that “Arma du Martin is the name that is mostly used by elderly people and farmers of Perti.