9 Contact-free optical, electrical and electronic linear and rotary control and switching devices; contact-free optical, electrical and electronic apparatus and instruments for linear and rotary controls; contact-free cross-faders, line-faders, rotary encoders and switches; electrical loudspeakers, electrical connectors, plugs, sockets, terminals, control knobs, handles, feet, and plastic parts for electronic, scientific and measuring apparatus, metal enclosures and switches