A tool for chip removing machining includes a holder and a tool head removably attached to the holder by screws. The disclosed control circuits, ruling over the parallel or series configuration of the two LED arrays, could be implemented in discrete forms or as integrated circuits. The internal locking device includes a locking bolt which when dis-engaged from the output shaft by an operator rotating the key allows the operator turn handle which turns the output shaft for the device unlocking the magazine doors. Additionally, the implant activator may be configured to selectively transfer power to the implant unit during the implantation procedure to cause modulation of at least one nerve in the body of a subject prior to final fixation of the implant unit to the tissue.