"Wick" by Knit One, Crochet Too, is a unique fiber combination of soy & polypropylene that has unique physical features ideal for spring & summer wear. Made of 53% soy & 47% polypropylene, it will keep you dry & comfortable in all temperatures & is a joy to knit up because of its silkiness & drape. The polypropylene draws any moisture away from the skin & gives the yarn its "wicking" ability. Terrific for worsted weight project such as socks, sweaters, and tops