RadioShack 4-Channel 900MHz Wireless Intercom with VOX Mode
- Consumer Alert: Most users do not need a license to operate this wireless microphone system. Nevertheless, operating this microphone system without a license is subject to certain restrictions: the system may not cause harmful interference.
- it must operate at a low power level (not in excess of 50 milliwatts).
- and it has no protection from interference received from any other device..