DK (double knit) is the most popular of all yarn weights - perfect for sweaters, pullovers and cardigans, accessories, kidswear and homeware. Usually knit on 4 mm. (US 6) needles (from 3.75 mm. (US 5) to 4.5 mm. (US 7) depending on your personal tension) DK yarn is sometimes known as 8 Ply or Light Worsted.