A generally flat instrument provides electrical interfacing between an electro-surgical signal generator and an exposed surgical electrode. Dome-shaped momentary contact switches are sealed within the instrument housing at points convenient for manual usage. Low profile switches which resist seal degradation are employed and the device is readily adaptable for accepting replaceable chucks containing a preselected surgical electrode. The relatively narrow elongated housing imparts the feel of a non-electrical surgical instrument. Inclusion of one or more nubs or other raised portions on the switch domes facilitates identification of switch function without requiring direct observation by the user.