Yarn Weights were first introduced by the Craft Yarn Council of America, the yarn industries trade association for more than 25 years. Their goal was to bring uniformity to yarn, needle and hook labeling and to patterns making it easier for manufacturers, publishers, designers and consumers to select the correct materials for a project and complete it successfully. These yarn standards can be downloaded from www.YarnStandards.com. Knitting yarn weights range from 0, lace weight, to 7, jumbo weight. The Standard Yarn Weight System has been adopted by most manufacturers, publisher and designers in the United States. The Craft Yarn Council of America is now reaching out globally to try to get the standards and guidelines implemented worldwide. Here we try to sort the yarn we carry by knitting yarn weights, to make it easier for you to choose the correct yarn for your project. We do advise you to still check your gauges by knitting a test swatch if you are substituting yarn.