Rechargeable Microphone: ● No need to purchase additional AA batteries. ● Microphone and receiver are built-in 1200mAh rechargeable lithium-ion 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 240ft/75m, 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. Bluetooth(10m). | Dynamic Vocal Microphone: ●Built-in dynamic unidirectional microphone core (dB value: 95dB/Audio signal: 48Khz/Frequency response: 50Hz - 16Khz), Vocal built-in boost circuit design is clearer. ●The outer shell of the microphone is alloy material which is harder, lighter and more wear-resistant, 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 6.35mm (1/4") or 3.5mm (1/8") 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.