Hippypotamus Stacking Toys are made with 100% pure food-grade silicone with NO added fillers, plastics or harmful chemicals! Free from BPA, BPS, PVC, lead & phthalates. Our stacking cups are soft & flexible, yet durable so they're gentle on gums and teeth. And because they're made with high quality silicone, they're completely safe for your little one to chew! Helps promote fine and gross motor skills, spatial perception, balance, problem solving, language development and creative play as they practice stacking, nesting and building with the various pieces. Encourages independent play with soft pieces that are safe and unbreakable. The Castle Stacker includes 5 pieces that are perfect for nesting and building and include basic numbers and letters to help with recognition. Multiple colors and sizes for your little one to build and explore. Perfect for bath toys and on the go! The nesting set is easy to clean and dishwasher safe. Make sure pieces are completely dry before nesting or storing away.