This heat sensitive thinking putty comes in a metal tin for storage. When temperature changes, color varies from purple to pink, orange to yellow, purple to blue or dark green to light green. You can knead, mold, bounce, twist and stretch it to relax, soothe your nerves, relieve stress at home or at work. Not only develops children's intelligence but also a funny toy for adults to release stress. It also is a good promotional gift on Christmas and Halloween.