9 months & up. Triblox Rainbow Silicone Triangle Blocks include 9 blocks made from toxic-free silicone that little ones can use to build, stack, and learn. Perfect for open-ended play, each colorful block features a number and corresponding illustration on the other side for added learning opportunities. Each block features a hollow design, perfect for scooping during sensory play and bath time. Triblox can be cleaned using a sterilizer, placed in a dishwasher, or washed with warm soapy water.