Simthread Polyester Embroidery Machine Thread Huge Spool 5500Y for All Purpose Sewing Embroidery Machines - 1White+1BlackWHITE + BLACK SELECTION - 2 HUGE Spools 100% Polyester Machine Embroidery Thread, 2nd generation Trilobal Polyester Yarn. Making the threads higher sheen, more vivid colors. Not only strength is important but the color fastness when it comes to laundering, chlorine bleach or any harsh chemicals individual.