sewing thread spec:10s/3,12s/6,20s/2/3 30s/2 40s/2/3 50s/2/3 60s/2 1. Counts:20/2,20/3,20/4 ... ,20/6,20/9,30/2 ... ,30/3,40/2 ... /3 etc.;2. Resistance to chemical ,abrasion resistant & excellent resistant to color change;3. Excellent strength-suitable for high speed sewing machine;4 ...