Sennheiser ew IEM G4 Twin GB-Band, Evolution Wireless In Ear System, Consists of: 2x UHF bodypack receiver (EK IEM G4), 9.5"" transmitter (SR IEM G4), and 2x IE4 earphones, Frequency range: GB-band 606 - 648 MHz, Stereo / focus / mono modes, Up to 1680 frequencies in 42 MHz switching bandwidth, 20 Channel banks each with up to 16 presets, Up to 16 compatible channels, Frequency range: 25 to 15,000 Hz, Frequency transmission via infrared interface, Pocket receiver with charging contacts for optional rechargeable battery (BA 2015 (NiMH)), Pilot tone, Autotune for lcating available frequencies, Audio Gain includes 60 dB, 4-Digit battery indicator on the transmitter and receiver, HDX compander, OLED display with NF level and channel display, 3.5 mm jack for earphones, Adjustable limiter, Switchable transmission power: 10/30/50 mW, WSM support (Ethernet interface for Frequency Management), Adjustable 6.3mm headphone jack on the transmitter, 1x BNC antenna socket, Inputs: 2x Jack / XLR female balanced combo, Power supply: 10.5 - 16 V DC, Includes a NT 2-3 UK power supply, 2x IE 4 earphones, 4x 1.5V batteries, GA 3 Rack kit for 19"" installation is included