Ridgid flex shaft 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. The flex shaft 1/4" Assembly, cable, sheath, couplings 50' Is an accessory for the k9-102 flex shaft machine.