8TC Protective Cap

Here's an oddity, and I've never seen one before.  

It's labeled "8TC Protective Cape." The "p" is shaped a bit funny but only a couple possible words made sense. [I doubt it's cave or cafe.] I ultimately decided that it says "cap" because I found a few other related items. The usual 8-track websites don't seem to have them. Kate's Track Shack has a few [LINK] but they seem to be different makes. The UK eBay seller Retronical seems to have an exclusive supplier for new covers, they're calling it a "tape end cover protector" using that particular modern SEO grammar. Functionally it's no different than a lens cover.

8TC no doubt stands for 8 Track Cassette. The device simply clips over the end of the case to protect the exposed magnetic tape.  The function makes sense, and it certainly works. You just have to follow the two instructions "remove to play" and "replace for protection", "replace after playing" or "replace to store." A couple note that they're made in England.

With terms like cap, protector and cover I found a few more makes, with different colors, slightly different sizes and shapes.  Currently I think this was more of a a fringe UK, product. A semi-disposable plastic something, lacking the utility and ubiquity of a 45-adapters.  I looked through 1970s issues of Billboard and reviewed ads from LE-BO, for the cases, and suppliers like King Karol, Ecofina, Ampak, Crest, Recoton etc. and there was nothing, no ads, no patents, no trademarks... nothing. They remain a mystery.