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