... /2, 30S/3, 40S/3, 40S/4 KEYSTONE Flame Retardant Sewing Thread Supply High Mechanical Strength, Flame Retardance, Abrasion Resistance and Smooth ... . Application: Glove, Bag, Mattress, Shoe, Uniform, Filter bag, etc4. Package: Sewing Thread Cone+Poly Cover KEYSTONE ARAMID FR ...