PFERD Policap Abrasive cone holder is available in tapered cylindrical shape. The holder expands during use. Matching, reusable holders in tapered cylindrical shape is available for using abrasive caps. The high degree of fitting accuracy between the components ensures that the abrasive caps remain securely attached to the holder during use. Specification: Diameter (inches): 5/16; length (inches): 3-3/8; Shank diameter (inches): 1/4; Recom. Speed RPM: 12,000; Maximum Rotational Speed (RPM): 20,000.