Underwater breather

---- In Die Another Day, James Bond, this time played by Pierce Brosnan, is issued a new updated version of the breather. It is used in the film to enter Gustav Graves lair in Iceland undetected.
Mirroring history, the prop was also made by the EON prop team at Pinewood studios, once again using a mixture of found parts alongside custom-made parts. The canisters this time were actually keychains in the style of miniature air tanks, manufactured by a sub aqua supply company to store full-sized air tank ‘O’ rings. These where re-purposed and added to a central aluminum body.
This prop was fitted with a more comfortable rubber mouthpiece from a commercially sourced snorkel. ---- (jamesbond.fandom.com)