Oh, that's just the sealed bag like normal. Back then, I was using special ziploc bags with a port for a small hand pump. They seem to have stopped making those, and I switched to a regular vacuum sealer.

The diy part was the heater/pump. I based it on this:

https://makezine.com/projects/sous-vide-immersion-cooker/

The problem with this design is that because it sits above the hot water, it tends to have a lot of condensation build up inside the housing. So I rebuilt it to have power plugs for the teacup heaters and pump. Then it could be set to the side, and I could use more heaters for larger containers.