YLI's Wonder Invisible Thread in Smoke (SMK)
Wonder Invisible is a very popular thin, clear monofilament. Use it for stitch-in-the-ditch, hand or machine appliqué, quilting when you don't want the thread to show, apparel hemming. Use the Smoke shade for darker fabrics. Wonder nylon monofilament will not melt with a home iron.
Invisible thread is used on the top (through the needle) normally with a thread such as a 50 weight or 60 weight cotton thread in the bobbin. It is not recommended to use invisible thread in the bobbin. Use the smallest needle you can - e.g. a 70/10 or 60/8 Microtex (Sharp) or Topstitch needle.
0.004mm (very fine!) 1500yd spool.