Stereo in-ear monitoring system for professional and semi-professional applications that features reliable JTS UHF PLL technology, providing 961 selectable UHF channels, and consists of SIEM 111R receiver, SIEM 111T transmitter and discrete in-ear headphones. As many as 16 sets of the transmitters can operate on the same stage – the system offers 4 groups, with each group having 16 compatible preset channels to choose from. This allows the monitor engineer to set up systems quickly and easily. Both the receiver and the transmitter feature an all-metal case construction and the JTS advanced circuitry that assures outstanding signal-to-noise ratio. The system provides the MPX Stereo Audio Transmission/Reception and is switchable to Mono operation if desired. The in-ear headphones seal off the ear canal with JTS designed Dyna-Driver ear buds which reduce undesired stage noise, ambient sound levels. 3 pairs of different sized Silicon sleeves are included to ensure a right fit for the users ear canal and comfort.