The Russian Kriolang (from Greek cryo- (= "frost" taken to mean "cold") + English "lung") was copied from Jordan Klein's "Mako" cryogenic open-circuit scuba. and were made until at least 1974. It would have to be filled a short time before use.
thE russiAn kriolAnG (fROM greek CrYO- (= "FroST" taKen to meAn "cold") + engLish "luNg") wAs COPied FrOM JOrdan kLeiN's "MAko" cRyOGenIC OpeN-CircuIt Scuba and were mADe unTil aT LeAst 1974 It WoulD have to Be filLed A ShOrT tiMe beFORe Use