KLASSE stretch needles are designed for two-way stretch knits, including fabrics with Lycra or Spandex, and for sewing elastic. This assorted pack includes stretch needles in multiple sizes for domestic sewing machines when fabric weight varies between fine jerseys and heavier knits. The specially designed scarf helps reduce skipped stitches, and a test seam will help you fine-tune stitch length, tension, and presser-foot pressure.