21 HEATSINKS FOR SEMI-CONDUCTORS; SWITCHES, ILLUMINATED AND ROTARY; INDICATOR LIGHTS; FOOT SWITCHES, HAND SWITCHES, PROXIMITY SWITCHES; KNOBS, PLANETARY DRIVES FOR DIALS, HANDLES, SHAFTLOCKS, SWITCH GUARDS, WATERPROOF CABLE CLAMPS; AND SERVO-CLAMPS, OLDHAM COUPLINGS, AND BELLOWS COUPLINGS FOR SERVOMOTORS, SYNCHROS AND POTENTIOMETERS