Sennheiser SR IEM G4 G-Band, Evolution wireless in-ear transmitter, Frequency range: G-Band (566 - 608 MHz), Up to 1680 frequencies in a 42 MHz switching bandwidth, 20 Channel banks with up to 12 presets each, Up to 16 compatible channels, Frequency range: 25 - 15,000 Hz, Frequency transmission via infrared