This is a Mobius scarf that is knitted using Size 5 - 40” circular knitting needles. You can use other yarns and change the needle size to two sizes larger than the stated needle size. For instance: If you are using a worsted weight yarn, a size 8 needle is usually requested. For this scarf, use a size 10 or 11 40” circular needle to give the drape and lacey look to the finished garment.