The TRE-936FFC features Ranger Exclusive new Advanced Noise Filter Circuit for improved signal to noise ratio, providing high noise rejection capability that others just claim they have. This one works! You will instantly notice marginal signals pop in better when you turn on the switch and listen to your reception with a quieter signal. The Advanced Noise Filter circuit de-emphasizes the audio high frequency response in order to increase the signal-to-noise ratio of weak signals. This provides you with the ability to receive those marginal signals with much more clarity and understandability. Combined with the Noise Blanker and the Automatic Noise Limiter, this has to be the quietest mobile stations ever manufactured.