Uniden’s Professional Series PRO520XL Heavy-Duty CB radio offers a full 4 watts transmit power, with RF gain control, and 40-Channel operation in a compact rugged construction CB radio. The PRO520XL has a front mount 4-pin electret microphone with extra-long coiled cord, S/RF LED meter, instant emergency channel 9, transmit indicator lights, Automatic Noise Limiter switch, Public Address switch, Volume control, Squelch control, and more.