An electric operating part assembly has a switching mat and switching mat domes which are arranged therein and which can be operated by the effect of a vertical force. 1 to 10 m thickness, and the resin layer contains 2 to 60 parts by weight of nickel with 0. Imidoorganosilanes can be prepared by a similar amine reaction between aminoorganosilanes and organoimides. The instrument further includes a driving tool configured for removable insertion into a proximal end of a passageway of the instrument.