The Mackie Big Knob Passive Monitor Controller is the perfect addition to any studio delivering professional source/monitor selection and precise level control that made the original Big Knob such a popular choice. Featuring an intuitive layout the Big Knob monitor controller features balanced/unbalanced 1/4 jack L/R source inputs along with 1/4 jack L/R mono outputs. Features Simple 2×2 monitor controller Choose between 2 sources and 2 monitors pairs Classic Big Knob volume control Mono mute and dim functions Pristine audio quality Passive audio path with no power supply needed Legendary Built-Like-A-Tank design Specifications Source Inputs: Balanced/Unbalanced Channel A: 2 x 1/4 Jack (L/R) Channel B: 2 x 1/4 Jack (L/R) 3.5mm Jack Mono Outputs: Balanced/Unbalanced Channel A: 2 x 1/4 Jack (L/R) Channel B: 2 x 1/4 Jack (L/R) Volume Control: Rotary Knob Controls: Source Select Monitor Select Mono Mute Dim