NADY U41QUADLTO Wireless Microphone System Four discrete UHF wireless receivers in a single rugged 19 all-metal rack mount housing for simultaneous operation of up to four transmitters Back panel balanced XLR mic level outputs; unbalanced  jack line level sum output with separate volumes; and external adjustable mute control for each channel Front panel LED display indicating TX On (single LED) and 5-segment AF levels for each channel