The Johnson 4230 is a 40 channel AM base CB Radio.It has a couple of nice features for the user.Has a dimmer switch on the squelch know that is activated by pulling the knob out.Has a noise blanker switch & it works pretty well at getting rid of local electrical noises.Also has a local or distance switch & an external speaker switch. The big red channels are easy to see & it has an LED S-Meter which operates on both transmit & receive.The radio can be ran with either AC or DC power.Also has a CB/PA switch.Stock transmit audio has good punch even with the supplied hand microphone. Receive is average but the internal speaker has a good tone.It's a nice radio for the Johnson or Classic CB Radio collector & can be found in many cases for less than $30 in working condition & is well worth the small investment.