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 offers 1 year warranty and free replacement service. Can write to us if you have any questions. We will be the greatest brand in the United States. Not supported MacBooks. Signal Stability&Against Interference: Bietrun dynamic wireless microphone with up to 98ft operating range, both outdoor gigs (weddings, pool parties, backyard BBQs, etc) and indoor use(class, singing, meeting)are easy for everyone. In the stable UHF frequency band, you can chain up to 15 wireless microphone systems to allow 15 performers to be onstage at the same time(Note: Need to lock ID first when multiple sets using ). Ease of use: The microphone uses a 2 AA battery(not included), and the receiver is USB-C rechargeable. 15 channels per microphone, you can switch it with the CH button. The microphone is equipped with an LCD screen thus it shows the microphone CH A/CH B, channel, battery power, and signal presence. Volume control via the Power Button, volume level from 1-5. Compatible with a karaoke machine, amplifier, mixer, PA system, and audio interface.Note: NOT WITH BLUETOOTH. Lossless Crystal Clear Sound: This wireless microphone karaoke is a dynamic cardioid mic that gives you clear sound quality thanks to high-fidelity audio technology. Gentle generous 50Hz–16kHz frequency response and presence boost to provide a sound that is clear and smooth.Perfect for family karaoke, small stages, clubs, places of worship, hotels, and gyms. Why not have hours of fun and no cords disturbing now?. Plug and Play, No Set up Required: Plug the receiver into karaoke machine, turn on the microphone then sing it loudly or deliver a speech! Never easy as this time. Bietrun wxm 31 wireless microphones are super friendly to everyone even if you have never enjoyed microphones. You won't have to set up the frequency matching, turn the microphone on, and the receiver automatically pairs with it.(Note: this wireless mic is incompatible with phones, computers, and tablets.).