The PSM900 Wireless Personal Monitor System from Shure offers an unprecedented combination of superb audio quality, robust RF performance, and category-leading features for the most demanding professional applications. All new, patent-pending CueMode allows the sound engineer to monitor different stage mixes with the touch of a button.
Precision front-end RF filtering significantly reduces dropouts from RF interference, and the enhanced digital stereo encoder provides excellent stereo separation and audio clarity.
Features: 
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
Category-leading Setup and Operation Features
Patent-pending CueMode allows monitoring of different stage mixes and storing of up to 20 separate channels on one bodypack for quick and easy reference
Front Panel RF mute switch for enabling or disabling RF transmission
Use Scan and Sync to scan the RF environment with the bodypack and assign the identified group and channel to your system over wireless IR link
MixMode Technology allows the bodypack user to balance the level of two separate channels while simultaneously listening to both signals in both ears
LCD menu with grouped menu items for easier user interface