For mounting polishing accessories with vertical shapes and 1/8" arbor holes. 1-3/4" overall length. 40000 RPM Max Speed. Left hand threads hold the accessory securely and self tighten while running in reverse operation in flex shafts and micromotors. Notch on bottom of shank identifies this mandrel as left hand threaded. Tapered or spiral mandrels allow the user to simply screw the accessory down onto the threads of the mandrel and once rotation begins it will automatically tighten onto the widening taper. This open thread design provides good stability throughout the length of the accessory. Tapered mandrels come in different shank and taper dimensions. Be sure to select the right one for the accessory and collet (or chuck) you intend to use.