Shure GLXD4 lavalier wireless microphone system

Digital audio clarity; Operates in 2.4 GHz spectrum; Rechargeable batteries up to 16 hours of runtime; Adjustable transmitter gain to optimize audio signal; Automatically moves away from interference without audio interruption; RF back-channel for remote control of transmitter functions; Globally-unlicensed 2.4 GHz frequency band allows operation of up to 4 compatible systems in a typical setting and up to 8 compatible systems under ideal conditions; Automatic transmitter power-off to conserve battery life when transmitter is not in use; To reduce set up time, the transmitter and receiver automatically link to form an audio channel the first time they are powered on and never have to be linked again. When setting up multiple receiver systems, turn on and link each transmitter/receiver pair one at a time to prevent cross-linking; Receiver Tuning Bandwidth 2400-2483.5 MHz; Working Range, Indoors, Up to 30 m (100 ft) typical, Up to 60 m(200 ft) maximum, Outdoors, Up to 20 m (65 ft) typical, Up to 50 m (165 ft) maximum; Output, XLR and ¼" connectors