|COATS&CLARK-Dual Duty All-Purpose Thread. This thread is sized for most hand and machine sewing. Dual Duty construction features a polyester core for strength and an outer wrap of long-staple cotton for smoothness and luster. It is mercerized and sews on all fabrics: natural or synthetic; knit or woven. This package contains one 400yd/365m spool. Available in white and black: each sold separately. Imported.