Audio Mute SwitchThe QT-5100 RefMic incorporates a non-popping, audio mute switch.  This enables the wearer to mute and unmute the audio without causing any audible popping.  This transmitter is ideal for Referees, Umpires and a variety of officials who only need audio for brief announcements.  This is also a good solution for corporate presenters who need a top quality audio experience that they can control.Remote Control Audio SystemThe QT-5100 RefMic utilizes RCAS™ (Remote Control Audio System) a revolutionary way to remotely control transmitter settings from a central computer or hand held remote control. The remote functions allow technicians to control; on/off, monitor status and battery level and make on-the-fly adjustments of frequency, mic gain, RF power level, mode and grouping, all wirelessly.3000 ChannelsThe QT-5100 RefMic offers approximately 3,000 channels. It is remotely tunable from 525 to 600 MHz in 25 kHz steps.Comfortable and ConcealableThe QT-5100 RefMic has a tough, composite hard case with belt clip.  This transmitter is the RCAS™ enabled version of our worlds smallest belt pack, the QT-300 BeltMic. Weighing less than 2 ounces and only a 1/2 of an inch thick, the QT-5100 RefMic joins the QT family as the most comfortable audio transmitters in the industry.Technical Data• Dimensions: 71mm x 42mm x 19mm• RF output power: 10 to 250mW (user selectable, country restrictions apply)• Number of channels: approx. 3,000• RF frequency range: 525 to 600 MHz• Switching bandwidth: 75MHz (25 kHz steps)• Modulation: FM• Nominal deviation: +/- 40 kHz• Peak deviation: +/- 54 kHz• Pre-emphasis: 50 us• Compander: Q5X DCS-QT• Signal to Noise: 110dB (A) RMS• Frequency stability: +/- 0.001%• Spurious Emission: