The Penatia is all over eBay. I bought about 14 of them when they were on clearance at BigLots. You have to drill a fairly wide but shallow hole at the end where the threaded ring goes in, a short piece of tube goes there and then the rest is a narrower hole with a concomitantly more narrow tube. I can't recall the precise dimensions and I can't tell you what sort of step drill would work 'cuz that's just too high tech for me. I just use plain ol' bits.
Penatia is made by cross. It's a real stiff nib but I like that. I rarely use a flexy nib. It's smooth as butter. Hey, it's a Cross product. They know what they're doing even if it's not ultra-high end.
Once you get it all turned there's just a teeny bit of material at the part where the wide but shallow tube is. Hence one can see through the material and note that I did not color my tubes.
The light box is a laundry hamper. I've been looking for them since I made this one with a laundry hamper I already had. Shockingly all the laundry hampers of this type that I'm finding are red or black, sometimes navy but never white. Whassup with that!