Master your performance. The Wireless In-Ear Monitor System by Gear4music is perfect for studio use and on-stage monitoring. Listen to clear stereo audio up to 40m away with no wires to hold you back. Complete with transmitter receiver and SubZero in-ear monitors (IEM) this wireless monitor system lets you perform freely. You can even use up to three of these systems at the same time so the whole band can be connected. All with a useful battery life of 30 hours.