Simplicity Pro embroidery thread by Brother is a durable, high sheen embroidery thread & is made of 100% polyester, which retains its color, heat resistance, and strength. The 40-weight, 1,100 yard spools are single-snap to help keep your thread from unwinding. The thread is specially designed and tested for Brother embroidery machines. For use with all Brother embroidery and combo embroidery/sewing combo machines, and other brands.