Product Features: 1. Compact wireless transmission system, built-in lithium battery, plug and play, easy to operate. 2. The most stable wireless propagation technology, UHF band, can eliminate interference problems even when multiple systems are used at the same time. 3. Not only suitable for XLR microphones, but also for guitar audio reception. 4. Compatible with dynamic and condenser microphones with built-in power supply. 5. Compatible with mixers, recorders, speakers, sound reinforcement systems, amplifiers, etc. Product parameters: Frequency range: 500 MHz - 599 MHz Channel distance: 0.5 - 2.5 MHz Setting: DOPSK Frequency stability: +3ppm Frequency response: 40hz - 20khz Receiving distance: 30m Voltage: 3.7v, 800ma lithium battery Charging time: 3 hours Usage time: 8 hours single transmitter package:package includes: Transmitter*1 Receiver*1 Charging cable*1 Instruction manual*1 Dual transmitter package: package includes: Transmitter*1 Receiver*2 Charging cable*2 Instruction manual*1