Cleans cassettes, chain rings, derailleur pulley wheels, brake arms, BB/crank interface and other hard-to-reach bike parts. Microfiber floss attracts and holds dirt instead of moving it around. 20" Microfiber ropes are highly tear resistant, durable and washable. Aglets prevent the ends from fraying. No more torn cloth in gears and fine parts! 20 ropes per pack.