Here’s some information about specifics from the video description:
I mount a uIEC/SD mass storage device internally in the case along with control switches, add JiffyDOS, a reset switch, and give it a new paint job.
This is such an awesome idea for a case hack and system modification. Nicely done!
If you want to pick up JiffyDOS or a uIEC/SD device, be sure to check out Jim Brain’s online store RETRO Innovations. The C64 Club highly recommends any products done by Jim Brain.