Well...I'm not entirely sure what this is...but it's VERY BRIGHT....
There are 12 yards of it, in 2 sections, it doesn't stretch longways, but stretches quite a lot crossways.
It's 14mm wide and came in a box with SUPER LAMA BRAID No 53 on it (see photo).
But, whatever it is, it will undoubtedly enhance whatever you've got....
I don't know the age but it came from an old haberdashery shop I cleared where most other stuff was from the 30s to the 60s.