This bundle includes everything you need for a stand-alone stereo spectrum analyzer setup. You get the Stereo Spectrum Analyzer, a Stereo Microphone, a Microphone Preamplifier Module, a Power Adapter Cable, and an AC Power Supply. The microphone can be conveniently placed on top of the Spectrum Analyzer (as shown) or positioned at a remote location.
Note that the stereo separation using this microphone is very low because the microphones are so close together (and they cannot be separated). For good stereo separation, using individual microphones is recommended.