 Surface-supplied divers will have the composition of the breathing gas controlled at the gas panel.Divers with long decompression obligations may be decompressed inside gas filled hyperbaric chambers in the water or at the surface, and in the extreme case, saturation divers are only decompressed at the end of a tour of duty that may be several weeks long.Equipment for planning and monitoring decompression includes decompression tables, surface computer software and personal decompression computers.