Nymo thread is an especially strong thread used for beading.  Nymo was created for the shoe industry to attach the bottom of the shoe to the top of the shoe. The sizing is somewhat peculiar, ranging from the thinnest "OO'' and "O" to "A", "B", through the thickest "F".  We carry OO and O which are great for earrings or any piece that requires you to thread and re-thread through a bead many many times.  We carry D which is good for necklaces and bracelets.  For bead stringing, you might still double-up the D thread for any piece.

We sell Nymo on small bobbins, large bobbins, spools (discontinued in 2007, but we still have some in inventory), and cones. The product on the small bobbins is slightly weaker and softer than that on the large bobbins, spools and cones.

Size D is most widely used.

NOTE:  Over the last several years, both the manufacturer and the distributor have changed the "color labels" from time to time.  
I guess, just for fun.