It's 10 layers of laser cut plastic which after peeling off the protective layer and building up as per instructions makes a stable well built case.
I had been up to now using the adafruit screen on a similar pi case bought cheaply off the net minus top two layers which worked fine but guessed I needed a proper case for the adafruit tft.
My pi that I used for this was being used with my weather station till I noticed this morning that the sd card socket was starting to crack, so after leaving it all day with gorilla glue carefully smeared over the sd card slot to strengthen where it was cracking it was dry tonight and ready to stick into the pibow.
The case sits securely around the sd card socket too which in my opinion will protect the slot from being broken. Although I cannot see the lights on the board itself ie boot light or internet it shouldn't really matter.
Everything sits perfectly and probably took me longer putting it carefully together than the soldering of the tft.
Certainly worth the money and looks great, the only con and maybe after pimoroni see this they might action it, a lid would be great to go over the top to protect the tft. Maybe turning the screws around the other way and having a lid that fits on plus four more nuts or maybe I'm just going nuts? Who knows.
I also got a third set of hands from pimoroni too, it took some effort to get crocodile clips attached, but I now have a decent station to hold electronics when soldering with a nice heavy base so it doesn't move, along with excellent arms. This is certainly better than the crocodile slide bar thing that I got with my soldering iron kit which to be truthful I don't use apart from the magnifying glass occasionally.
Thanks again www.pimoroni.co.uk for stocking these two great products.