Weird Nippon Kogaku lens hood (and step-up ring?) Info please...

[MadisonWI]

Hello,

Recently found a Nippon Kogaku marked accessory that seems to be a lens hood, that comes in two pieces, with a nice cap for the rear threads?

I can't seem to find another like it online or on eBay, and I can't figure out which lens it was designed to go with?

The Nikkor-S 5cm f1.4 has 43mm threads, but the shape of the hood seems more telephoto?

Here's my eBay post with pictures and a description: Nippon Kogaku Tokyo Lens Hood Step Up Ring Adapter Nikon 43mm 57mm S2 Camera | eBay

Any information is much appreciated.

Thanks!