Sculptex is a non-toxic, non hardening modeling clay that is sulfur-free and non contaminating. Sculptex is an ideal alternative to sulfur-based clays, which are incompatible with some mold rubbers. It holds excellent detail and is great for precision sculpting, prototyping and model making. Sculptors who have used Sculptex say that it’s the perfect replacement for Klean Klay. Sculptex is available in EXTRA SOFT, SOFT, MEDIUM, & HARD.