1. Product Features: Wireless transmitters and receivers can be used for electroacoustic instruments such as guitars, bass, violins, and the like. 2. Ultra-high frequency 730mhz acoustic transmission, anti-interference, ultra-short delay. 3. Support 4 groups of devices to use at the same time, the maximum transmission range can reach 50 meters. 4. Built-in rechargeable lithium battery, long working hours, with USB cable, easy to charge. 5. Plug and play, easy to use, small size, light weight, easy to carry. specification: Audio response range: 20Hz-20kHz Frequency: high frequency 730mhz Transmission range: max.50m (accessible); 30m (through wall) Transmission delay: less than 4ms Power: Built-in 3.7V 600mah rechargeable lithium battery Charging time: 2 hours Continuous use time: 6 hours Charging port: micro USB Product size: 11 ?? 4.5 ?? 1.5 cm / 4.3 ?? 1.8 ?? 0.6in Packing size: 17.5 ?? 10.5 ?? 5cm / 6.9 ?? 4.1 ?? 2in Package Weight: 250g/8.8oz