For those of you (like me) Polymer clay is just a name brand, any oven bake clay will work. This was a little too difficult for my 3 and 5 year old to complete. I did most of the work as the clay was too hard for little hands to mold, but they loved helping me, picking colors, twisting and of course poking the holes. We also used the leftover clay to form beads to place alongside the shells. Looks great.