3M 7010326816 Back-up Pad is a black, medium-density pad suitable for metalworking applications such as deburring, finishing, grinding, polishing, and surface preparation. It can be used with disc sanders and right-angle grinders. The pad has a quick change attachment style and a TP abrasive attachment type. It is compatible with various sub-industries such as builders hardware, medical instruments, metal fabrication, metal implants, plating & polishing, plumbing fixtures, and turbine engines. The thread size is 1/4-20 INT, and the inside diameter is 0.0 NP.