It is an air-drying modelling material mixed with a special fibre, which strengthens the product when it is dried, making it harder and tougher than normal air-drying clay. It is relatively fast drying (depending on the size of the project) and will completely dry within 24-48 hours. Once dried the project will hold its shape and be durable. It can be painted with acrylic paints to perfect the final outcome. It is perfect for creating model figurines or for decorative projects around the house. Air Hardening Clay needs to be kept in airlight storage in order to remain soft and not dry out. Its shelf life is approximately 1.5 years.