The SteppingStones™ are made of Resource-Saving EPP (Expanded PolyPropylene). This material is Water-, Saliva-, Bite- and UV-resistant. But more importantly, this material is extremely light, yet enormously strong:
Each tile weighs only 180 grams, but is loadable up to 265 lbs!
All corners of the SteppingStones™ are rounded, so no sharp edges that could hurt your child.