The ProSpec 1U4M4S has four mono mic/line inputs and four stereo line input channels.

The is a professional, single-rack-space analog audio mixer featuring four mono mic/line channels with Burr-Brown preamps and four balanced stereo line input channels.  Key Features & Specifications

• Inputs: 4 mono channels with Neutrik XLR/TRS combo jacks and individual 48V phantom power, high-pass filters (75Hz), and inserts; 4 stereo line channels with balanced 1/4" jacks. 

• Outputs: Balanced Left, Right, and Mono/Center XLR outputs utilizing THAT Corporation OutSmarts devices.

• Control & Monitoring: Front-panel illuminated switches, individual PFL solo, panning/balance controls, and independent 8-segment LED metering for L/R/M outputs. 

• Audio Design: Wide-bandwidth, low phase-shift circuitry derived from larger APB console designs like the Spectra and ProDesk.