Shure PSM900 Wireless Personal Monitor System with SE425CL and P9RA (X1 Band) Exceptional Audio Quality... Enhanced digital stereo encoder provides a wider stereo field with exceptional separation, enhancing audio detail and clarity Patented Audio Reference Companding sounds more like wired Robust RF Performance... Precision front-end RF filtering, the same found in industry-leading UHF-R wireless systems, significantly reduces RF interference for a cleaner, stronger RF signal, fewer dropouts, and less audible artifacts Exceptional transmitter linearity vastly reduces frequency intermodulation and allows up to 20 compatible channels per frequency range Auto RF gain control prevents signal distortion due to RF overload before it can affect performance