NOTE: Please turn down the volume of MIC input on your speaker or amp to the lowest before plugging the receiver,and then turn on the mic, turn on the receiver, then turn up the MIC input volume slowly to avoid speaker screeching or damage to amplifier.Please place the mic right under your mouth for better sound. Quick Troubleshooting: 1.Make sure the microphones and receiver have enough power; 2. Plug the receiver into a MIC input, not other interfaces; 3. Turn off the microphones and receiver, and then turn on to repair(How to repair- turn off the mics and receiver and turn on again, when the green light on receiver stops flashing, they are connected successfully.). What You Get: 1×UHF Wireless Microphone, 1×Receiver, 2×Built-in Rechargeable and Replaceable Batteries, 1×Dual USB Charging Cable, 1×6.35 mm (1/4'') to 3.5 mm (1/8'') Gold-plated Converter, 1×Anti-slip Ring, 1×User Manual. We are always here to help if you have any questions. Wide Compatibility: This rechargeable wireless mic system comes with a 6.35mm to 3.5mm converter, making it accommodate more devices like amplifiers, PA system, karaoke machine and powered speakers etc and good for occasions like conference,speech, Web podcast,YouTube recording, Outdoor recording, Yoga instructor, church,Family party, Opening Ceremony, dancing instructor, Promotion, game etc. Plug and Play: The Karaoke microphones and receiver pairs automatically once are on power. Adjustable Frequency Range; Not compatible with Bluetooth speakers, MacBooks and phones.Please make sure you plug in MIC jack, not AUX in, Audio in or Line in, otherwise no sound can be heard. Wireless Professional Microphone System: Updated UHF microphones supports transmission distance up to 200feet (60M) without distortion or loss of sound. Other features like stable signal, no delay, no radiation, anti-howling, anti-jamming, distortion <0.1% and adjustable frequencies. Long Working Time: This wireless microphones system for karaoke is built with three rechargeable and replaceable batteries inside both the microphone and receiver; Charge for 3-4 hours, and they run for approximately 10 hours, which is also environmentally friendly in place of tons of AA batteries!.