Methods for selecting finishing devices to perform finishing operations on a print run. The handle includes a ball with a smooth surface surrounded by a hollow socket. Furthermore, a ferroelectric memory 5 which stores correction data for correcting the reference potential, a data latch circuit 7 for storing correction data that has been read out, and a microcomputer logic unit 6 for controlling ferroelectric memory 5 as well as data latch circuit 7 are provided.