Extra heavy DuPont® KEVLAR® Thread, TEX 166/2, extra strong with 60 lb breaking strength. Excellent for all your heaviest sewing needs (compare the thread size with the thickness of the penny shown in the second picture).
Ideal for heavy Leather stitching, Shoe, Boot, and Luggage Making or Repair, Saddlery, Canvas sewing and especially for Fireman's Boots, tools for fire performances (fire spitting, fire eating) and toys for fire play, as KEVLAR® is heat resistant up to 750° Fahrenheit (begins to decompose between 800° F and 900° F). There is no flame or fire proof synthetic fiber, so KEVLAR® Thread will decompose if you hold it into a flame (mean temperature of a candle flame: 1,500° Fahrenheit!).
TO AVOID ANY CONFUSION: My pictures show, as you can see on the third picture with the quarter, a Master Spool with 5.000 yd of thread. You get one spool with the thread you order in one continuous length.