This is a Chain adjuster tool for the small rear hub Ducati motorcycles. It is used to turn the eccentric hub that tightens the chain. Proper chain adjustment is very important because a loose chain is dangerous and can lead to serious damage. It is CNC machined out of billet aluminum and clear chromate plated to give you many years of corrosion free use. All of our tools are made in the USA by us and come with a 100% satisfaction guarantee. This tool fits: 748 916 996 998 Hypermotard Multistrada Monster S2R S4R