It is a DIY module, and uses an Arduino Nano as the brains of the module using Port manipulation with an r2r ladder for the CV output. I did a whole bunch of videos on the different aspects of this module which you can see here:
Explaining PORT MANIPULATION: https://youtu.be/IoJasVtr0OA
Part1: https://youtu.be/7Mhq-GJlMeM
Part2: https://youtu.be/WDeVrf_H2IQ
Part3: https://youtu.be/BoewbbyEvRc
here is the build video: https://youtu.be/z-7DU65izWw
You can buy the PCB and Panel and or components here: https://www.tindie.com/products/Sourcery/sth-sith-sample-or-track-and-hold/
Or you can download the files from this page and order the parts yourself, or even just follow the schematics and use protoboard or similar to build it. What makes it a bit special is the Max and Min pots which makes it so you can tweak the range of the cv output. Also with some fun effects by inverting the output for some fun effects. You also have an internal noise source which you can output by using the internal noise source and going into Track mode. This will output the noise as long as hold is not triggered.