Orthopedic Inserts

The guy showed up inserts with very high arches made of a rigid material. I mean it was cork, but I'm not sure. It was NOT gel, mousse or anything sweet like that. What is a rigid material that people sometimes use to make inserts?

Mine, custom, had a metal plate in it. I also said was, as usual, because I ended up getting rif of them for two reasons. One was that they hurt my feet. Two. I found a way to put your back arch of my foot and did not need any kind of help. Here's how I did the following:
Ask your foot on your lap. Take both thumbs and place them side by side and place them in the back of the arcade, opposite the heel. Push them hard enough and hold it there. Relax. After 30 seconds, slowly lift your toes as high as you can. Then release the pressure, but keep your toes there is still 30 seconds. I felt the arch back in my feet and it also authorized the cracking that has been around the bottom of my feet.