At first I thought they might be off an early Motic wild clone (their newer ones have 10x/23 eyepieces but the older ones were 10x/21) but the pair I have are different with 10x/21 stamped or engraved on at the top.
After a bit of googling, it turns out Wild made "10x 21c" eyepieces which were just marked with white paint which wears off easily (two eBay examples posted), unlike other Wilds with more permanent markings. Not sure what these were on originally, maybe a cheaper student stereo? They give as great a view as any Wild eyepiece though. It's also a bit funny since the 10x/21a and 10x/21b eyepieces are high-end focusable eyepieces seen on surgical scopes, the M10 and generally their most expensive wares, while this is marked in the cheapest way possible and they are not focusable.
The upshot is you can sometimes get genuine Wilds for unmarked eyepiece prices if you keep an eye out.
A couple photos from eBay showing the original and a pair that are almost worn clean.
They also made a version with a silver tube that looks a little different but is also basically identical.