Originally Posted by QuiltE

Thanks for clearing that up ... I had wondered about it.

Also, re "Wonder Invisible" mentioned by SewingSenior.
Have been wondering if there is a product by that name?

Or should it be the InvisaFil thread by WonderFil?
https://www.wonderfil.ca/invisafil/
https://www.wonderfil.ca/longarminvisafil

It's a 100 wt thread, fine as can be, yet works well for FMQing because it is still a strong thread.

I've also used it for hand sewing for EPP, applique work, and even on bindings.
Comes in 60 colours, but because it is so fine, it is virtually invisible.