Chavant NSP Medium non-drying modeling clay is a professional-grade, sulfur-free oil-based sculpting clay. It softens when warmed and hardens at room temperature. Because it is sulfur-free, it prevents curing inhibition when using silicone molds. Solvents such as naphtha, mineral spirits, and turpentine can be used to smooth or dissolve the surface. It can be reused many times, making it economical. The content is 2 pounds (906g).