Worsted and Aran (sometimes known as Heavy Worsted) are the perfect medium weight yarns to knit up to protect you against the cold of winter. They are also the most commonly used weight in knit and crochet, and when held double create a bulky weight. You will want to shop these yarns for projects calling for a 5.50 -6.50 mm crochet hook or 4.50 - 5.50 mm (US 7-9) knitting needle. Worsted weight can be used for any gauge calling for 16-20 stitches per 10 cm. Worsted and Aran yarns are often used for projects such as cabled sweaters, blankets, and cosy accessories such as hats and scarves