Jewelers use #8D Handpiece. Slim collet handpiece for fine detail work. Pre-lubricated ball bearings require no maintenance. Chuck guard slides back when changing burs. Comes with 3/32" and 1/8" collets and chuck wrenches for changing collets and accessories. Duplex springs are subject to breakage. We recommend that only experienced users of flex shaft tools whose work demands the added flexibility consider purchasing this style handpiece. For most users, the "straight" handpiece is the preferrable solution.