Great work Theuns
The part you are referring to is the diluter/demand regulator, manufactured by Draeger who (I think) are still in business. That version was a 1933 design, most visible in a Bf 109 E cockpit. I would have to check what type of regulator was fitted in the Ju 87.
Luftwaffe flying helmets incorporated a throat mic so wearing a mask at low altitude was not necessary for communication. Oxygen masks changed in style over time too, but my memory says they did all incorporate the hose, unlike some allied masks to which a hose, fitted in the aircraft, was attached. In a typical 'Stuka' attack profile the attack commenced from around 12,000ft (or less), so not high altitude by the standards of the day.
Cheers
Steve
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