1. Volume On/Off switch.
2. Squelch - lower the noise threshold allowing only the strongest, hopefully clearest, signals through the speaker.
3. RF Gain - limits the receiver's ability to receive more distant signals permitting only stronger nearby signals to be received.
4. Clarifier - on radios equipped with single sideband capability it is used to permit reception/transmission of signals at the same point on the frequency as the station with which you are trying to communicate.
5. Mode Selection Switch - Allows operator to choose between communications modes the radio is capable of using. In this case, AM (Amplitude Modulation), USB (Upper Sideband), ND LSB (Lower Sideband).