RAF Stereoscope 14B/2455

[Hallibag]

Has anyone seen one of these before? I came across this example today and it’s a type of stereoscope that’s completely new to me, and my online searching has turned up nothing. Perhaps someone has a list of Air Ministry stores reference numbers, and would be kind enough to tell me what it says for 14B/2455? I’d at least like to know when it dates to.

[Rescue190]

Interesting item. Thanks for sharing.
John

[Hallibag]

Yes, more complicated than the common 14B/746 stereoscope. I especially like how you can adjust how far apart the lenses are. My guess is this one is older.