Help me ID this ltm-M adapter

[Ducky]

I have an ltm-M adapter that came on a lens and it has no manufacturers name.
Around the face, starting at the red dot, it says: M6-M7 50mm 75mm M2 50 M3 28-50mm.
Does anyone know who made it and what it may be worth?
Thanks.

 

[Sonnar Brian]

Post a picture. Lots of them coming out of China without manufacturers name. I've seen some made-in-Japan without manufacture's name, but it was M2-M3 generation.