Mono-Poly smoke colored polyester thread from Superior Threads is used to show off the quilting but not the thread. Size .004, 2,200 yards, Iron and Dryer safe, Will not become brittle over time, will not discolor, strong with low stretch, soft and pliable. Recommended by quilt artist Hollis Chatelain. Recommended needles: Topstitch 70/10 or Microtex 60/8.