Gütermann elastic shirring thread - 8387 Light Grey 10m
Composition: 36% Polyurethane and 64% Polyester.
Gutermann elastic thread is perfect for gathering, crimping and shirring. It can also be very handy as a tracer yarn for knitting and crocheting work.
Used as the bobbin thread, not as the needle thread when shirring, wind the elastic carefully by hand. Some sewists swear by winding without and tension and some prefer to wind with a little hand tension. It will depend on your machines tension, so do take note of any tension adjustments you may make to the bobbin.
Seamwork have a great article on shirring that you should check out prior to beginning your first shirred project!
Janelle of Rosery Apparel has a great dress tutorial worth a look that features shirring to really get your creativity flowing.