FireLine BLACK SATIN 4LB 0.005 diameter (50 yards) is designed for extra strength:

This beading thread is super strong and extremely flexible. It is made from polyethylene, one of the strongest fiber cords ever made. Fireline is both a superior fishing line and a favorite beading thread. It works great in beading projects requiring multiple passes through small bead holes. It is very durable, feels and works better than the finest bead thread but is as strong as jewelry wire. Most beads will not cut this thread. This Black Satin Fireline will not leave residue on your fingers. 

FireLine BLACK SATIN 4LB 0.005 diameter (50 yards) specifications:

• Color: Black Satin
• Country: USA
• Strength Test: 4 lb
• Material: Polyethylene
• Diameter: 0.005 inch , 0.12 mm
• Quantity: This FireLine Black Satin 4lb 0.005 diameter (50 yards) is sold on a 50 yard spool