First usage dates for openback inflateable, single zip boots, hinge bridge N&G etc

[BOBC]

Hi,
Trying to establish introduction of kit dates, approx.

When did the open back inflateable schwimmweste start appeaaring ?

Either issue orders or someone wearing one.
A photo where a date for the capture or death of one of the occupants of the photo is my normal method, gives a date for the item in use at that time !

Also ditto for the hinged bridge Nitsch and Gunther goggles.

Single zip flying boots.

vertical release panel on wearers left Tan coloured flying overall.

Cheers

BOBC

[Rheinmetall]

The inflatable open-back schwimmweste was introduced in late 1940 and I have seen several in collections having dates of manufacture from Sept.1940 onward. Have even seen photos of these in wear during that same time frame.