Shure PSM 900 In-Ear Monitoring System consists of a P9T transmitter, a P9RA bodypack receiver, and a pair of SE425CL in-ear monitors. The system features an enhanced digital stereo encoder that enhances audio detail and clarity, and patented Audio Reference Companding that sounds more like wired audio than other competing wireless systems. Patent-pending CueMode technology lets you monitor different stage mixes, as well as store up to 20 different channels on a single bodypack receiver. A Scan and Sync function creates an IR link between the components for fast and easy syncing. RF muting provides easy setup without creating RF interference. RF scan and automatic gain features provide excellent RF stability and channel availability, and prevent dropout due to RF overload. MixMode technology lets the receiver balance the levels of 2 audio channels while receiving each signal in both ears simultaneously. The transmitter has a compact half-rack design with XLR/TRS combo inputs, loop outputs, and a 3.5mm headphone jack for monitoring. It also has a backlit LCD display and LED level meters. The receiver has a slim aluminum housing with volume and balance controls and a 3.5mm headphone jack. It has an LCD screen for navigating settings and menus, and it operates on a pair of standard AA batteries. The included in-ear monitors provide high-quality audio and a secure in-ear fit, ideal for professional musicians.