Compact in-ear monitoring set for foldback of an audio track or stereo mix. Comprising a matching transmitter and receiver unit, both of which are rechargeable from USB. Audio is connected to the transmitter via 3.5mm stereo jack and the system is supplied with a pair of in-ear headphones to connect with the receiver. Operating on the licence-free 5.8GHz band, the 2 devices pair automatically on power-up and use a frequency-agile system to maintain the link. For groups of users listening to the same audio, additional receivers can be purchased and paired to the same transmitter to receive the same signal. If different audio is needed for users, up to 4 transmitters can be operated in proximity of each other, depending upon the wireless traffic in the area. Designed for accurate and convenient wire-free monitoring for stage performers, presenters and sound engineers.