The Hisonics Wirelese Headset/Microphone combo unit includes 2x Wireless
Microphones, 2x Wireless Headsets, and 2x Wireless "clip on" type
microphones. Any two of these devices can be used at one time. Each
microphone's volume can be adjusted independently, and the unit has a
range of 300 feet from the base station. It includes several outputs to
connect to many different external speaker types.