Mono/Stereo Button Monaural or Stereo headphone reception may be selected durning FM reception by alternately pressing the Mono/Stereo Button 9 The Speaker On/OffSwitch 7 must be in the Off Lock Switch To Prevent accidental changing of any of the radio settings move the Look Switch 3 to the locked position. When engaged in the locked position the icon key D will appear in the LCD display. To release the lock switch simply move the switch to the off position. Make sure lock Switch 3 is in off position when radio is to be used as radio is completely inoperative until lock switch is released. If the radio is not to be used for any extended period of time,battery power saving may be relized by setting lock switch in its locked position during storage.