They're nice, VERY light enclosures, but I do not recommend them for something other than an arboreal, really, and for something that's OK with 12" height. I do wish they opened in front instead of on the top, but for $10 dollars each (ON SALE for 60% off, that is, what with the going out of business sale) it was a good deal. I'd have bought more if they had more than two available.
The background was made using foam (that pink foam they sell at home depot), silicone, and a craft cement, and acrylic paint mixed in. Extra water added and multiple coats were put on it. I used sandpaper to add texture to some of it, and dry brushed lighter and lighter for the added effect...
This was actually my first attempt at doing a background like this, so I'm pleased with the results. It's smoother feeling than it looks, too.