Panasonic 12" 12GB Optical Disc Cartridge [LM-R13000, re-writable video disc]

Description

This listing is for a rare vintage rewritable industrial digital video cartridge from Panasonic (aka Matsushita). The only recorder/player ever produced was the LQ-D5500, and the format didn't have a proper name, as this LM-R13000 was the only media produced for the recorder.  I've seen a couple of the recorders for sale (there's one on eBay as of this listing), but never a disc cartridge apart from the lot these are from (shipped direct from Japan).
The disc you'll get is sealed in the original packaging and as far as I can tell brand new, but has obviously been sitting in a warehouse somewhere for the past 25 years, so there is no guarantee whatsoever that the discs are actually usable if you do have a recorder; these are sold as-is.  They theoretically might be usable, but I have no idea what conditions they were stored under, and I wouldn't get my hopes up even if you do have a recorder.
To repeat:  Although they are new and sealed, these discs are very old and sold as a display piece, with no guarantee the media is actually usable.
Note that the unboxed disc in the photos is of one that I opened and kept for my own collection; the box you'll get is sealed unless you specifically request I open and check the contents.  Also note that the orange metal disc labels of the two I opened appeared to have gradually creeped down about a half-inch, so it's very likely the sealed ones are the same. I was able to gently pry the label up with a metal ruler and reposition it without damaging anything, and the glue still seems surprisingly strong, but I can't guarantee that's the case for the others.  If you explicitly request, I can open the box and reposition the label for you before shipping it.
Non-US Global Shipping program buyers only: Please notify me before paying and I will package the disc(s) you are purchasing for shipping and give an exact size and weight, which might affect the international shipping cost once eBay gets their hands on it.
There is very little information about the format online; some information I've gathered that may be of interest to vintage media fans like myself:
12" phase-change rewritable optical discs in a sealed cartridge
12GB 2-sided cartridges stored 41 minutes of SD 4:1:1 compressed digital video (or 73,000 still frames) + 2 channels of 48kHz/16-bit PCM audio
Discs were one frame per revolution and could capture individual frames, so the recording presumably did not use inter-frame compression
The recorder/player had a head for each side, so the cartridges were not flipped
Claimed to be re-writable at least 10,000 times and readable at least 1,000,000 times
According to a catalog page I have, discs originally retailed for ,100 and the player cost ,000