Pentax ME - Circular translucent thingie

I recently acquired a NOS Pentax ME in its original packaging. Included in the box was a translucent plastic circular thingie about 3/32” thick with an approximately 3/8” hole in the center. The diameter is a bit more than 49mm. I remember one of these was in the box with an ME Super I purchased for a former spouse. I couldn’t figure out its purpose then, and upon seeing this one, my curiosity was piqued again. I can’t find anything in the user manual about it so I was hoping some you Pentaxians on here could enlighten me on what this curious item is used for? It looks like it may be a diffuser of some sort but it’s too large to fit the 49mm thread of the typical M-series 50mm lens (the item isn’t threaded for screwing into anything anyways). Your advice on this thing would be appreciated.

Stan

Baseplate protector/spacer for tripod screw......stopping the thread screw from bottoming out in the camera socket leaving the camera insecure maybe?

Mike

Base-spacer was my first thought too.
My Canon AE-1 came with a similar disk made from black rubber. It is mentioned in the manual as intended to yield more friction between camera base plate and tripod head when using long lenses, seemingly due to the leverage.
To my mind it also may yield space on a large tripod head, with elastic cover, for the breech lock- and aperture-ring of the lenses, which protrude exactly to the base line of the camera.



I guess at least the additional friction or the scratch protection at uncovered tripod heads is the idea behind your disc.


Or of course something completely different...

I’ll be damned! After reading your responses I went back to the manual and the section about tripod mounting mentions the use of a spacer ring (packed with the camera) under the camera when using some large diameter lenses! My brain (back then and now) totally didn’t make the connection between that verbiage and the plastic disc. The manual only shows the thing edge on in the illustration. I feel really dumb now. The small size of the M-series bodies would probably require that with some lenses. Thanks guys!

Stan

As very long lenses had been beyond my funding I just memorized that disc was for lifting up the camera due to the breech-lock ring and lens-controls. But so far I never used it, but I still got it.