Vintage - Fascinating Siam dancerssilver nielloware cufflinks - 1940's or 50's

Another one where I'm thinking this would be something my Granddad would wear, but mainly because the 'backs' are like some of his military type accessories....but I'm hoping you can help me with the right terms for what these clips are called (it's on the tip of my tongue but I can't get the word for the life of me).

Are these generally a male vs. female item? I can re-categorize as needed.

I think the dancers are wonderful to look at. I couldn't even tell there was anything on the clips until I used the magnifier!

And as for time period...um....how can you tell??? No marks found on backs.

Valentino97 solved the mystery!