Wireless Microphone with Bluetooth Receiver: Built-in high sensitivity professional Dynamic Unidirectional microphone core, transmission distance upgrade to 160 feet (Open place), Bluetooth 32 feet. ◆Enhance Signal stability, No delay, No radiation, Anti-howling, Anti-jamming, Constant frequency. ◆The mic outer case is alloy material which is harder, lighter and more wear-resistant.(Not compatible with TV). Plug And Play Microphone: No need pair. ◆Only for input devices with 6.35mm (1/4") or 3.5mm (1/8") MIC interface, E.g speaker, Singing machine, audio amplifier, PA system, Voice amplifier, truck speaker system, Dome speaker system etc.◆Rechargeable Bluetooth receiver, which can be connected to smart phone to karaoke on the speaker. Or as a Bluetooth receiver to play music on old speakers.◆Turn on the receiver, search for the Bluetooth name: Bietrun, Play your music for karaoke. Enhance Battery Working Time And Display: ◆The chargeable receiver is built-in 1200mAh battery for 8 hours use time and fully charged in 3 hours.◆The microphone does not come with any batteries, we recommend using 2 AA Amazon alkaline batteries. ◆The display can show the battery power and signal strength in real time, don't worry about Suddenly not working. Multipurpose Microphone: Built-in moving-coil Cardioid microphone,widely applied to conference,speech, Web podcast, Yoga instructor, church, get together, Family party, Opening Ceremony, dancing instructor, Promotion etc. ◆If you use multiple microphones at the same time, Please Open the microphone battery cover to switch channels otherwise there maybe noise or no sound(Each microphone channel number is inconsistent to avoid interference). 1-Year Warranty And Precautions: If your microphone has no sound, make sure you have enough power for the microphone and receiver. Insert the MIC jack, Not an AUX jack. Bietrun offers1year warranty and free replacement service.Can write to us when you have any questions.We will be the greatest brand in the United States.Not supported Bluetooth speaker and MacBooks.