The Frogmen is perhaps one of the coolest vintage scuba movies ever made.  Hollywood sacrificed accuracy, but made some great underwater fight scenes.  This is a rare window card from a cinema that showed the 1951 film.  The US UDT divers used Aqualungs, drysuits, and triple tanks even though the Cousteau Aqualung only existed in France under the control of the Germans.  The Japanese divers used rebreathers.