Best Dual UHF Wireless Microphone with Volume Control + ECHO Function. No Need To Set, Just Plug and Use! Perfect for Karaoke, Speech, Meeting, Performance, Indoor or Outdoor..No need to buy batteries! Rechargeable UHF Dual Wireless Microphone With Receiver System. Both microphones & receiver can be rechargeable. Each Microphone with 2200mAh rechargeable battery; Receiver with Built-in rechargeable battery. When full charged, microphone working time about 10 Hours, receiver working time about 5 Hours; Dual USB Charging Port for Charging..1/4 Inch(6.35mm) Receiver Input designed for Outdoor Karaoke Speaker, PA Speaker System, Power Amplifier, etc(Notice: Not For Phone, PC, Camera). Microphone & Receiver use UHF Connection Technology; Working Range about 100ft(30m); Frequency Response 50Hz-18kHz; SNR >70dB; Distortion <0.5%; Latency <3ms; 10 UHF Work channels(CH01-CH10)..Support 10 sets at max for Simultaneously Using(Each Set Using In Different Channel). Notice: If Microphone & Receiver can’t connect with each other, they need Pairing to Reset, please see how to Pair/Reset in User Manual..Advanced connection and after sales: 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. If you find no sound from the mic, you need to re-pair.