The SR5.1MKIII has been upgraded with a 47 position stepped attenuator made exclusively for Coleman Audio. Fold down for stereo and mono capitablity. Front panel channel trims and mute switches allow proper calibration and easy evaluation of signal localization. Inputs are XLR / TRS combo jacks to allow easy interconnection with the A/B5.1 Surround Switcher, or other equipment, in any environment. Outputs are XLR connectors.