3" Roloc Rubber Back-up-Pad. Backup pad designed to support 3M™ Roloc™ 3 inch diameter abrasive discs. This pad has a 1/4-20 INT thread which allows it to be mounted directly to tools with 1/4-20 EXT threaded shafts. Assembly also includes a Roloc™ shank and adaptor. Max Speed 20,000rpm. (Priced Per Each). - 6.4mm Shaft.