Climax Metal, SD-048048-06NL, Nut Lock Type Rubber Expansion Sanding Drum with Shank, 3/8" For mounting abrasive sanding sleeves. Sleeves are secured in place by controlled expansion of solid rubber drum spindle. Rubber expansion is controlled by tightening/loosening of the hex nut. The rubber spindles is seated directly on the drive mandrel/arbor. Rubber provides cushion for smooth, even finish. Features: Rubber expansion is controlled by tightening/loosening the hex nut The rubber spindle is seated directly on the drive mandrel (arbor)