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.