PRO DUAL WIRELESS MICROPHONES: Built-in high sensitivity professional Dynamic Unidirectional microphone core, transmission distance upgrade to 160 feet (Open place). Enhance Signal stability, No delay, No radiation, Anti-howling, Anti-jamming, Constant frequency. The handheld mics with all Metal Design, which is harder, lighter and more wear-resistant. | PLUG AND PLAY: No need pair. Can Only Plug In equipment with Mic input, E.g speaker, Singing machine, audio amplifier, PA system, Voice amplifier, truck speaker system, Dome speaker system etc. Can't Plug In AUX input, Otherwise No Sound can be heard.(Not Compatible with Bluetooth Speakers and Laptop) | BATTERY AND DISPLAY: The chargeable receiver is built-in 720mAh battery for 4.5 hours use time when 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 | PERFECT WIRELESS MICROPHONES PERFORMACE: Built-in moving-coil microphone,widely applied to conference,speech, Web podcast,YouTube recording, Outdoor recording, Yoga instructor, church, get together, Family party, Opening Ceremony, dancing instructor, Promotion, game etc ●If you use multiple microphones at the same time, Please switch channels(●Part 4 Advanced Operations to 2 note B,Page 8 in the manual) otherwise there maybe noise or no sound | BEST 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.