Polymer Clay Baking Surfaces 

No all mine it's just one side. I bought mine at the home depo bout really any tile store. They can be put into the oven. I have had this one and a few others and just used one the other day with no problem. So they last a very long time. Ceramic tiles are meant to get hot and the 250 ish to 300 heat isn't high enough to really hurt them. Some rock can even be heated in the oven too. Wear oven mitts when taking them out and lay down on a towel to let them cool naturally. Hope this helps.