Features: 1. Wide Applications: The wireless transmitter receiver can be used for electro-acoustic instruments such as guitar, bass, violin, etc. 2. Stable Transmission: The wireless transmitter receiver features the high frequency 730mhz sound wave and excellent 20-20KHz full frequency response, which ensures more stable and clear signal transmission, anti-interference, short delay. 3. Maximum Transmission Range: The wireless transmitter receiver supports simultaneous use of 4 sets of equipment, one-to-one and no interference. The maximum transmission range of it is 50 meters. 4. Built-in Battery: The wireless transmitter receiver features the built-in rechargeable lithium battery, long working time, USB data cable, and it is easy to charge. 5. Easy to Carry: The wireless transmitter receiver is small-sized, light weight, easy to carry, featured by plug and play. Specifications(about): Audio response range: 20Hz-20kHz Frequency: high frequency 730mhz Transmission range: max.50m (barrier-free); 30m (through the wall) Transmission delay: less than 4ms Power supply: built-in 3.7V 600mah rechargeable lithium battery Charging time: 2 hours Continuous use time: 6 hours Charging port: USB Product size: 11x4.5x1.5CM/ 4.3x1.8x0.6in Packing size: 17.5x10.5x5cm / 6.9x4.1x2in Packing List: 1 * Transmitter 1 * Receiver 1 * USB Charging Cable 1 * Instruction