Got this with a bunch of older astro stuff, mostly Takahashi, looks to be a focal reducer or some such.
No ID markings on it at all. Inside threads on the end that looks to be the end that accepts a camera or some such are 42mm (peak to peak) but NOT Pentax thread. Likely the threads of whatever go into this will measure close to 43mm. I would think the threads would be designation 43mm. I notice Takahashi used 43mm threads a lot.
Male threads on the other end that likely goes into the scope drawtube are 60mm.
Glass appears to be multi-coated, probably a singlet but might be a doublet (the edge of the element/group is not easy to see). Element/group is convex on the scope side, looks to be flat or nearly so on the camera side.
A Google Image search on "Takahashi focal reducer" didn't help, nothing that looked like this. I'd be surprised if this a Tak product, I don't think I've ever gotten anything Tak that didn't have their name on it.
Anyone know who made this and what scopes it goes to?