Adopts UHF technology, remote wireless transmission makes operation easier without annoying wires, can achieve 20m of the transmission distance. Broader frequency range, less interference, showing your voice easily and perfectly Adopts the exacting complete electronic circuit control, capture rich, full-bodied sound from sources that are directly in front of the microphone. For all events like Karaoke, live-performances, conference, church, school, hall, party, etc. USB receiver power supply by USB charger,powbank and more. Suitable for studio / karaoke / radio / etc V20: frequency: A: 262.85MHz B: 268.85MHz distance: 30-50s PCB board: +5-9V Audio frequency response: 40HZ~15KHZ Audio dynamic range: more than 100dB Audio output: 0-200mv Maximum operating distance: more than 80 meters/m Receiver power supply voltage: 3.7v-4.2v (lithium battery) Receiver working current: less than 80mA Receiver continuous working time: standard (3.7v/800mA) 10 hours Transmitter working current: less than 80mA Transmitter working time: 10-18 hours Color: black Material: plastic Size: 250x50mm Package Contents: 4 x pair of microphones 4 x adapter 4 x connection line 4 x receiver (Without battery) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.