Pro audio mixers that are 24 channels or fewer are typically listed in this category. There are some pro audio mixers that have 32 channels and are still in this category, because they are small enough to fit on a desktop. These mixers are used for small bands, disc jockeys who need to do some work with a live band, or as a mixer for use with anything that needs a bunch of microphone inputs.
When choosing a desktop mixer, you will note that some have built-in power supplies which use an IEC AC cable, just like the kind that plugs into your computer or computer monitor. Others have an external power supply that has a cable that attaches to the mixer and then has a big black box, and then a cord that goes to the wall. Still others have "wall warts".
Finally, these mixers give you one more decision you have to make. The smaller mixers, 8 or 4 channel mixers in general will have rotary knobs for the volume on each channel. Others will give you linear faders, you know the ones that slide up and down. That just about wraps up what you can expect to find in our "Desktop Mixer" category.