The Big Knob Passive Studio Monitor Controller from Mackie is a monitor-control solution that allows you to choose between two audio sources and two monitor pairs. It can be used for project and professional studios and is designed to increase your workflow for recording and mixing applications. It features mono, mute and dim functions and delivers pristine audio quality. Built with the classic Big Knob volume control, it is designed with a passive audio path, which requires no power supply. The Big Knob Passive Studio Monitor Controller is sturdy and has a "built-like-a-tank" design. Plus a Hosa CSS-105 cable features rugged molded plugs and a durable outer jacket for long-term use.