A device, which, when used in climbing, acts as an anchor in cracks with two parallel sides. The device consists of several opposing cams that rotate on the same shaft. The force generated when a climber falls is counteracted by the force of the friction between the cams and the rock. As opposed to other known spring loaded camming devices, the load generated by a fall acts on the cams, and not on the shaft, through cables that pull on the cams on the side of the shaft opposite the edge that is in contact with the wall, and which are supported on convex surfaces formed by the cams themselves.