On each there is a set of number that look like this. Some say 70/3, some say 30/3 or 60/3 like the pink one above. The larger numbers seem to indicate smaller threads just like tatting thread is sized.....and I am thinking that the /3 might mean 3 ply? All are follwed by a number indicating the length of thread on the spool, and are of the brand "Zwicky". I looked around online a bit, and didn't find much information on this thread, its' possible that it is no longer made.
Anywho, this was my big happy surprise today. Not that I'll have time to play with it of course! I just put one darling down for a nap, and of course now the other is beckoning from the bassinet. Such is life!