ACTIVA-Plus Natural Self Hardening Clay. Plus clay is a premium quality natural self hardening clay. It's exceptional plasticity and ultra fine grade allows for excellent detail and versatility. It air cures to superior strength and durability (will not crumble) with minimal shrinkage. Can be carved, sanded and drilled when dry and accepts virtually any finish. If desired Plus clay can be kiln dried. This package contains 2.2 lb/1kg of white clay. NOTE: clay lightens in color as it dries. Imported.