WIRELESS SYSTEM: HEADSET (HEAD) UHF wireless home system with headset microphone. Perfect for applications such as karaoke, teaching, training, and conferences. The 600mA/3.6V lithium battery works for about 4 hours. The receiver is recharged via a 5V USB socket with a standard smartphone adapter or by connecting the USB to a computer. Operating distance 30/40 m. The transmitter uses 2 AA 1.5V batteries.