It's anodized aluminum. I got plain anodization, but you can select colors, raw aluminum, and perspex. You can select the thickness also. I went with 3 mm because it was less than $1 more than 2 or 2.5, but 4 mm was like $6 more.
I used their program, which is pretty awesome. My favorite thing about it is it gives you pricing for your design internally. You can "value engineer" your design, get your pricing on the spot, then submit the order all from within the program. I was initially going to engrave "18/16" on it, but it ended up increasing the cost 50% so I just used a sharpie when it got here.
I loaded DXF files into it from my CAD drawings but it reads SVG also. With DXF, it only reads the outlines, but I don't know about SVG. You can add holes and engraving in their program if you want.
There appear to be a lot more options than FPE for this kind of thing if you're using Illustrator or Inkscape. I'm not a CAD guy, but it's way more intuitive for me than those other programs. I also wanted aluminum rather than acrylic, but I see that Hermes uses acrylic so I'm sure that would work and it opens up lots more options.