Shure GLXD-RE14/SM31, Wireless fitness headset system, GLXD advanced aerobic system, Digital 2.4 GHz wireless system that includes the GLXD4RE 9.5"" receiver, the GLXD1 pocket transmitter, and the SM31 fitness headset, Up to 11 systems simultaneously, Up to 9 systems under typical conditions with WLAN and Bluetooth devices (with the implementation of the optional UA846Z2 frequency manager), Automatic frequency setup, Pilot tone, Microprocessor-controlled antenna diversity, Displays battery life in hours and minutes, Remote controllable transmitter gain, Integrated battery charge port, Metal pocket transmitter, Metal receiver, Detachable antennas on the rear side, XLR and jack outputs, High-resolution LCD display, Up to 16 hours of battery life, An up to 60 m range, SM31 FH condenser microphone, Frequency range: 60 - 20,000 Hz, Directional characteristic: cardioid, UA802-RSMA antenna cable, 95A21651 USB cable, PS43E power supply, Incl. Shure lithium-ion battery, rack kit and the SM31