Sanding Drum Mandrel, 1/2 x 1/2 inch, Foredom Style A-SD188. Expanding Rubber Sanding Drum Mandrel with 1/8" shank. For use with 1/2" dia. x 1/2" long (13 x 13mm) sanding bands including aluminum oxide bands. 1-7/8" overall length. 40000 rpm max speed. See the Sanding department for the bands.