One transmitter and four receiver. 2.4GHz wireless in-ear monitor system create your personal or band monitor system. Solid RF connection over a 90 feet range(actual range depends on RF signal absorption, reflection and interference) Up to 107 dB signal-to-noise ratio provides clear, detailed audio at any volume. High Resolution 24-bit/48kbps audio. Broad 20Hz-20KHz frequency response. Dynamic Rang 107 dB. Less than 5ms Latency, Simultaneous broadcasts on 6 channels. 5 hours of battery life(rechargeable battery for both transmitter and receiver) Provides smooth frequency response with any headphones.