From Manufacturer
The Revolabs Executive HD 4-Channel Wireless Conference Microphone System (No Mics) is an intuitive and easily installed 4-channel wireless microphone system for conferences, meetings and other group discussions. This system supports up to 4 Revolabs wearable, tabletop or plug-in microphone transmitters (not included) and features a 4-channel rack base and 4-bay charging station.
Intelligible speech is reproduced at CD quality, with a frequency response of 50Hz to 20kHz. The system is completely free of battery operation. Drop the microphones into the charging station and enjoy up to 8 hours of operation on a full recharge. The microphones are also impervious to radio-frequency (RF) interference from PDA and cell phone devices and 128-bit encryption keeps transmissions secure.