Shure ADTQDC-G57 Axient Digital PSM ADTQ Quad IEM Transmitter with DC PowerReady for the most demanding live environments, including large scale concerts with multiple on stage performers, the Axient Digital PSM ADTQ Quad IEM Transmitter with DC Power from Shure allows monitor engineers, RF engineers, rental houses, and production companies to deliver four stereo channels or eight mono channels of legendary Shure audio quality to their talent's ADXR bodypacks and preferred in ear monitorsall from a single rackmount unit