The West Mountain Radio CLR/dsp installs between your radio and your station's speaker. It features a Clearspeech® DSP noise reduction Processor with 3 watt amplifier. It provides extremely effective noise reduction for voice and Morse code. It has a five postion rotary switch for: OFF, LO, MED, HI, and MAX noise reduction. When you plug in headphones (not supplied), it disconnects your external speaker. A Red LED flashes to indicate digital overload "clipping".