Yarn for crochet is usually sold as balls or skeins (hanks), although it may also be wound on spools or cones. Skeins and balls are generally sold with a yarn band, a label describing the yarn's: - weight - length - dye lot - fiber content - washing instructions - suggested needle size The thickness or weight of the yarn is a significant factor in determining the gauge. Thicker yarns generally require large-diameter crochet hooks, whereas thinner yarns may be crocheted with thick or thin hooks. Hence, thicker yarns generally require fewer stitches, and therefore less time, to work up a given project. Patterns and motifs are coarser with thicker yarns and produce bold visual effects, whereas thinner yarns are best for refined or delicate patternwork. Yarns are standardly grouped by thickness into six categories: superfine, fine, light, medium, bulky and superbulky. * Tip: Save the yarn band for future reference, especially if additional skeins must be purchased.