Radial Engineering MIX 2:1 Two-Channel Audio Combiner and MixerThe MIX 2: 1 is a simple yet highly useful mixer that passively sums two audio channels down to one. This enables you to easily sum the stereo outputs of a console, recording interface, or portable playback device down to mono, or to mix any two signals together and balance their relative input levels. Features: Mix two channels to a single mono output Individual level controls can be bypassed when not in use Balanced 1 4" TRS and XLR inputs