THREAD SPOOL: Features one 2,200 yard spool of Superior Threads MonoPoly 100% polyester thread that is extra fine at 0.004" (.1mm) in diameter (90 denier) FINE THREAD: Superior Threads MonoPoly thread is extra-fine 100% polyester which makes the thread heat resistant, iron and dryer safe (medium heat), strong with low stretch, soft and pliable, and will not discolor or become brittle over time INVISIBLE THREAD: Strongest invisible thread on the market, MonoPoly is commonly referred to as an invisible thread due to its fineness and reduced-sheen, great for the bobbin or top PERFECT FOR CRAFTING: MonoPoly threads are great for quilting, appliqué, apparel, or wherever reduced sheen invisible thread is required MACHINE USAGE: For best results with home machines, use Topstitch #70/10 needle - lower top tension; For best results with longarm machines, use #14 needle (MR 3.0) - lower top tension