Mono in-ear monitoring system for semi-professional applications that features reliable JTS advanced technology, providing 16 UHF PLL selectable channels, and consists of SIEM 2R receiver, SIEM 2T transmitter and discrete IE-1 in-ear headphones. It provides over 60 meters of stable operation distance. Both the receiver and the transmitter feature lightweight engineering plastic cases and the JTS advanced circuitry that assures outstanding signal-to-noise ratio. The receiver also features a built-in limiter to protect hearing. The in-ear headphones reproduce full range of frequency, natural mids, and full highs and bass, and 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.