Shure BLX14/MX53 Q25, UHF Wireless System, With BLX1 pocket transmitter and MX153 ear strap microphone, SM Presenter Series, Up to 12 systems simultaneously, Pilot tone, Microprocessor-controlled antenna diversity, Quick-Scan function for free frequency detection, Condenser Earphone Microphone MX153: 20-20,000 Hz, omnidirectional, Plastic receiver, Integrated antennae, XLR and jack outputs, Audio status LEDs, Frequency range Q25 742 - 766 MHz