Made specifically for members of the Royal Navy who additionally qualified as Ships Divers
Measuring 25mm x 22mm x 3mm
Back includes a single "butterfly" style clip for attachment
RN SHIPS DIVERS: Officers and Ratings from all branches could apply. Members of the RN who volunteered as Ship's Divers underwent a one-day aptitude test, concentrating on swimming ability and suitability for diving.
Those selected went on a four-week course, which consisted of basic compressed air (open-circuit) diving. There was also extensive instruction (and practice) on searching ships bottoms for explosives, as well as instruction in working on ship's hulls, decompression chambers and maintenance of diving equipment.
On completion, the diver returned to his ship or shore establishment PINSand to maintain their qualification (and get their diving pay) were required to dive for at least 120 minutes during each four-month period.