Features: The wireless headset microphone adopts UHF band to avoid signal interference at all times. Its signal transmission distance is up to 30 meters (without obstacle), 2.5ms transfer delay, more reliable and stable for transmitting pure sound. A/B channel will avoid the distraction of the same frequency by changing frequency when using the same frequency. (Channel A: 600~649MHz, Channel B: 650~699MHz) The included receiver adopts 3.5mm audio plug, which allows it to be directly plugged into any audio without connecting an output cable. Also provide a 6.35mm audio adapter. (can be directly plugged into the bus/car audio and outdoor draw-bar speakers, etc.) Built-in 400mAh polymer lithium batteries in the headset microphone and the receiver. Battery runtime can be up to 5 hours. With low battery indicator and low battery shutdown function. With DC-5V USB charging port. The headset microphone and the receiver adopt the miniature design, which are compact, lightweight and portable. ABS+metal materials are dampproof and corrosion resistance. Can be used for teaching training, tour guide, music playing, KTV singing, family entertainment, conference hosting, etc.