Ultra-light clay is made by mixing vacuum microspheres (polymer foaming powder), polyvinyl alcohol, crosslinking agent, glycerol and pigment in a certain proportion. It is a non-toxic, odorless, non-irritating and new type of environmentally-friendly handmade craft material.

Ultra-light clay is much lighter than plasticine because of its large swelling volume and small specific gravity, which is generally 0.25-0.28 g/cm3. The weight of the dried product is 1/4 of that before drying, which is extremely light.

In addition to being light, ultra-light clay has many advantages compared with traditional plasticine. Take Rover ultra-light clay commonly used by my children as an example. It has no pungent smell, good tensile strength, bright color, non-sticky, easy to form, and the formed works are not easy to crack. Children have been playing with ultra-light clay since kindergarten. More than half of my handmade works are made of ultra-light clay by children. Now the children are in primary school, and the works of childhood are still there.