..not the same as High Density polyethylene (aka Visions). Expanded foam PVC comes in thicknesses of 0.1 inch to .25 inches. Boaphile cages use roughly .25 inch thickness or close to that. The material has a smooth hard surface on each side with a somewhat soft and less dense core. If you push your fingernail into the center soft part on a cut piece you leave a dent. As a cage material, it flexes (which is a good thing = no cracking) and insulates nicely. It is also easily repaired if necessary. The material conducts heat very well when heated with Flexwatt.
I think this material is great for cages for tropical animals like boas. It is fairly light in weight as well. It holds in heat far better than HDPE (Vision cage material) but isn't as tough.
The color sheen is satin, not glossy, so don't think you're getting shiny black or shiny blue cages. No shine here. The blue color is quite bold though, and that is my favorite. The yellow isn't as bright as you'd think. The gray is very nice, as is the white. I don't care for the black - it looks like soot IMO.
The acrylic doors are really simple and functional - just what you'd want on a cage housing larger snakes.
One of the best features of his cages is the heating option where he laminates the Flexwatt under the cage. You save yourself alot of work and trouble by getting that option. Then, if you need more heat in the cage, just run Flexwatt along the back wall of the stack.