It consisted of a cage on wheels with a fireproof double-pitched roof padded to absorb the blows from enemy missiles (as in the ditch-filling tortoise). It was crowned by a three-storey turret equipped with catapults on the upper level, while the lower levels held reservoirs of water for the extinguishing of possible fires. On its floor, there were ram-holders mounted on supporters (“kriodoche”), i.e., a series of cylindrical rollers upon which the battering ram moved easily with traction ropes on each side. The operators, who were positioned at both sides of the ram, pulled the ropes backwards and forwards, causing the ram to strike the enemy wall with great force. With the fluctuating inclination of the ram-holder, they managed to strike the wall on the desired target. The right side of the model has not been completed for better visual understanding.