RF Modulation- GFSK(Gauss frequency Shift Keying) Frequency band- 2.4 GHz (2405-2478MHz) Frequency response- 35Hz-14KHz±3dB Signal/Noise- 84dB or more Distortion- 0.05% or less (32Ω,1 KHz,65mw output) RF output level- 3mw RF Output Power <10mw Earphone output level- 32Ω,65mw Reception sensitivity -90dB +/- 3dB / 0dB=1V/Pa，1kHz Audio input connector- 3.5mm mini jack Operation range- 60m (197ft)(without obstacle) Power requirements- TX4 PRO: 3v DC (Two AAA size batteries) / BY-WM4 PRO RXU: Supplied by USB Type-C device Plug- BY-WM4 PRO RXU: USB Type-c Connector Consumption power- Receiver: 3V/70mA Transmitter: 3v/70mA Dimensions- TX4 PRO:45x70x35mm / BY-WM4 PRO RXU:82×30.7×12mm Weight- TX4 PRO:47g / BY-WM4 PRO RXU: 9.5g