Samson EarAmp EWM100 is a wireless stereo in-ear monitoring system comprising the ET100 transmitter and ER100 receivers. It operates in the 470–502 MHz UHF band with a 32 MHz tuning bandwidth and a 300 ft (90 m) line-of-sight range. Audio is 25 Hz–15 kHz ±3 dB with SNR >100 dB and THD <0.9% at 1 kHz. Powered by 2x AA batteries (receivers) for up to 8 hours; includes Zi150 earphones and a rackmount kit.