The Acerbis Chain Guide Block easily replaces the entire O.E.M. unit and ensures durability and high resistance to shock and wear from the chain. Made of PA6, it is made of two parts that allow installation without removing the chain. 100% PA6 construction. Highly resistant to shock and chain wear. Made of two pieces, allowing to be mounted without removing the chain. In the event of collision or contact with roost, material won't bend. Features removable / replaceable lower insert that can be replaced independently if it wears out.