The all-in-one XSW IEM SET includes the XSW IEM SR stereo transmitter, XSW IEM EK stereo receiver, IE 4 in-ear headphones, external power supply, and a rackmount kit. The system provides up to 6 hours of continuous use with two AA batteries in the receiver—at a range up to 330'. The transmitter can send signal to as many receivers as you want (additional receivers available separately). Up to 12 transmitters can operate simultaneously in the same frequency band.