ALEX TOYS-Air Hardening Clay. Create all kinds of artwork from clay pots to jewelry with air-hardening clay. This paper-based clay can be molded into an endless number of shapes and used in a variety of techniques. Finished pieces will harden overnight so there is no need for an oven! Store any unused clay in an airtight container or bag. This package contains 1lb/480g of white colored clay. Conforms to ASTM D4236. Recommended for ages 3 and up. WARNING: CHOKING HAZARD-Small Parts. Not for children under 3 years. Imported.