12b61dae_rium__Let_Your_Brain_Run_Free___Other_products
[PlayFoam] PlayFoam NEVER dries out or hardens -- even when left out! [Other products] 
Others harden when left out of the package overnight. It is a one-use product.
Playfoam & Smencils : BRAIN-athon Emporium: Let Your Brain Run Free!
Other products