It's not plastic. It's baking clay, actually, but it's probably the best to use in relation to what general sculptors use. It's called Super Sculpey. It's tough to an extent, but it has the ability to crack if too much pressure is embedded into/on to it. I had to scrap some peg holes from stronger plastic to be inside of the clay, so it could slide through, while being tight, and not cracking the piece.
