micro yards

Material thickness is usually measured in units of 1/1000 of an inch, called a "mil". Are you sure the letters are "my" and not "mil"?

It looks like some kind of unit, but I can't figure out what unit it is. I highly doubt it means 'yottametres' because that would be far, far too big. Where is the text from? Is it likely to use imperial or metric units?