Rechargeable Microphone No need to purchase additional AA batteries Microphone and receiver are builtin 1200mAh rechargeable lithiumion battery Working time up to 7 hours plus with charging time of 3 to 4 hours Charging cable is included in the package supports charging the dual microphones and receiver in one cable at the same time Cool LED ring light runs in green charges in red and an upgraded clear white LED display UHF Wireless Microphone Pro The microphone adopts UHF frequency band use legal signal bands with US FCC ID open place UHF distance 240ft75m signal stability Receiver with Bluetooth or as a Bluetooth receiver to play music on old speakers Turn on the receiver search the Bluetooth name Bietrun play your karaoke music Bluetooth10m Dynamic Vocal Microphone Builtin dynamic unidirectional microphone core dB value 95dBAudio signal 48KhzFrequency response 50Hz 16Khz Vocal builtin boost circuit design is clearer The outer shell of the microphone is alloy material which is harder lighter and more wearresistant this microphone has a better weight and grip experience for conference speech web podpodpodcast instruction church family party opening ceremony dance instructor promotion etc Easy to use and 15 adjustable channels Plug and play automatic connection press the microphone tail switch to turn on the microphone 15 adjustable frequency channel for each microphone if you use multiple microphones at the same time or noise click the switch at the end of the microphone to adjust the channel Keep each microphone channel number inconsistent to avoid interference Multiple Compatibility Only for input devices with 635mm 14 or 35mm 18 microphone interface Compatible with party speaker singing machine amplifier PA system audio interface truck speaker system dome speaker system and more equipment with microphone input