JOYO digital wireless transmitter and receiver. High-quality voice, all digitals, 2.4G Audio transfer makes us flounce away the bondage held by wire while playing. 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 6-8 pairs are operating simultaneously within one meter. They do not have interference by each other, wireless routers, bluetooth devices, etc. Signal to Noise and Distortion: greater than 87dB. Supports "One to Many" (one transmitter to one or many amplifiers). Low-latency. Rechargeable battery: lithium battery (included; lasts for approximately 4-5 hours after a charge of 2 hours).