Elastic, practically undestroyable stringing material.
Coil on one bobbin is approx. 10 metres. New supply is on different coil, then the previous one, but the quality remains the same.
The biggest advantage, besides extreme firmness, is cross-section. This elastic is flat so you can string tiny pearls (e.g. seed beads 3mm on it. Flat elastic is also excellent for more sophisticated bead patterns.
bead stringing, beading