The RCBS .20 Caliber Pilot/Neck Reamer was designed specifically to be used with the hand-operated RCBS Case Neck Turner, not the Trim Pro Power Case Trimmer. This tool is caliber-specific, designed to turn both the inside and outside of .20 caliber cases simultaneously. The RCBS Case Neck Turner is a handy tool that makes quick work of trimming your case necks to uniform thickness for increased accuracy. To make the most of this tool, however, you need a caliber-specific pilot, like the RCBS .20 Caliber Pilot/Neck Reamer, to trim your cases to the proper thickness.