This is the very original design that I made for the NV spyglass I'd set out to create.
It's a very elegant design, and very thick walled which makes it more robust, but more expensive to for Shapeways to produce.
I've included it anyway. It's an old design, but it still works well.
As with all of my flanges, it was made to fit a p8079HP cascade tube image intensifier. A cheap item common to military surplus retailers.
It should be used with the earlier style, single lug rear flange.