From manufacturer datasheet: The Shure Model SCM810 is an automatic microphone mixer using Shure's patented IntelliMix operational concept. Intellimix activates only those microphones being addressed, minimizing the poor audio caused by multiple open microphones. The SCM810 is an eight-channel mixer capa ble of being linked for installations as large as 400 input channels. The single-rack-height chassis is ideal for installations with limited rack space. The removable header-type input and output connectors are quick, convenient, and eliminate the time and expense of wiring XLR microphone connectors.