JOYO JW-01 Rechargeable 2.4Ghz Audio Wireless Digital Transmitter Receiver Guitar,Bass,Mandolin,Banjo w/ FREE Tuner High-quality tone, all digital signal, 2.4GHz, UHF frequency Transmission distance of 20-30 meters indoor; 80-100 meters outdoor. Unlike analog transmitters, our digital system is not affected by outside signals or phones This unit works well even when 4 pairs are operating simultaneously within one meter. They do not have interference by each other, wireless routers, bluetooth devices, etc Dynamic Range: &gt;87dB. Supports "One to Many" (one transmitter to one or many amplifiers) Battery: Lithium battery (included; lasts for approximately 2 hours after a charge of 2 hours)