I think this Body looks like the same i've buyed on ebay Months ago for 150€. I make a custom Binder 691 Connector by my own self with a lathe. I'm right? :
The insert i have had made in bakerlite with gold plated turned pins. You can though order an insert that fits. Numerous outlets have them, it is the gx25-9 aviation insert.
I like the swivel though it is large in comparison to the body diameter.
I dont like the idea of a custom connector though, finding tuchels is a pain and there were thousands produced.
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Alas there is No love here...