Sennheiser EW IEM G4-TWIN-A Wireless Monitor System (A: 516 to 558 MHz)The ew IEM G4 Twin Wireless Monitor System Kit from Sennheiser is an addition to Sennheiser's evolution family of wireless monitor systems. It includes an SR IEM G4 transmitter, two EK IEM G4 stereo receivers, two pairs of IE 4 earphones, a rod antenna, a GA 3 rackmount kit, and four AA batteries. This kit can be used as a rugged two person, all in one wireless in ear monitoring system for applications in live stage, theater, or house of worship