18 months & up. Make building a captivating experience with this collection of Click Builders. Young children can design an infinite number of structures, which will improve their fine-motor skills, creative-thinking skills, and problem-solving skills. The transparent colors will also teach children about color patterns-especially if they play with these builders on a light table. This set universally connects with other builders. Smallest block size is 1.25". 72 piece set.