the back of the harness can unclip from each other at the shoulders. There is no automatic gas control: so safe use of the set relied entirely on training. Other similar rebreathers British "frogman's" sets used the same shape of counterlung as the CDBA but different cylinders. One type was the "Swimmer Canoeists Breathing Apparatus" (SCBA), which had oxygen cylinders on the back, vertically for better streamlining in swimming, the oxygen connections thinner, and no cylinders on the front, leaving the diver's lower front uncluttered for climbing in and out of small boats. The SCBA gave 90 minutes dive duration with no reserve. In mixture (nitrox or heliox) mode it was called SCMBA. An old photograph seems to show the cylinders (and perhaps also the weights) in a tied or laced canvas casing rather than held on with metal clamps, and a rectangular fullface mask as with the CDBA. There is a British armed forces manual about the SCBA, dated 1984 as if the SCBA was still in use then, showing separate eyes-and-nose mask and strapped-in mouthpiece and no canvas pouch, and separate sport-type weight belt with buckle-shaped weights all at the back. The design of the Swimmer Canoeists Breathing Apparatus likely changed down the years. The LOSE (Lightweight Oxygen Swimmers Equipment), a diving rebreather formerly made by Siebe Gorman, was similar to a Swimmer Canoeist's Breathing Apparatus including the cylinder backpack. Other British frogmen's sets had no back cylinders and one or more big cylinders across the belly: one of these modes was the UBA (Underwater Breathing Apparatus). Other meanings of those initials The letters "SCBA" had two other meanings connected to breathing sets: Submerged Chamber Breathing Apparatus (formerly used to aerate submerged air-chambers). Self Contained Breathing Apparatus (its modern meaning, it means industrial breathing sets (usually open-circuit) for use on land): see SCBA. For other uses of the letters "UBA" see UBA. See also References External links CDBA Teardown: detailed description and many images. http://www.therebreathersite.nl/Zuurstofrebreathers/English/universal_rebreather.htm description http://www.therebreathersite.nl/Zuurstofrebreathers/English/photos_universal_rebreather.htm pictures http://blog.tekstremediving.com/2006/09/25/the-dssccd/ Diving with a CDBA, with images CDBA