The THAT JAM is a bass-compressor in studio quality, but in a compact pedal. It uses only high quality parts, the THAT JAM is based on the THAT4301P, used in some well-lnown studio compressors.

Here is the link to the thread, where you can also find fantastic building instruction, the text is only available in german:
Workshop - THAT JAM

This kit contains all parts to build the THAT JAM, also a BB enclosures is included!
Knobs are not included, you can select the ones you like best in the shop. You can use all knobs for 6,3mm shafts a diameter up to 16mm. Also not included are sheets to label the enclosure, those also can be found in the shop.

Here is the partslist.