Ridgid FlexShaft machines utilize specialized chain knockers attached to a flexible cable that are spun at high-speeds by a cordless drill attached to the center drive Shaft. Since the cable spins inside a durable nylon sheath that is housed within a fully contained drum, there is less jobsite mess. Chain knockers expand for full Pipe cleaning, which result in a wall-to-wall clean. RIDGID 64298 chain knocker features 1/4″ Cable, 2″ Pipe, and 2 chain.