18 months and up. These chunky, translucent, interlocking builders are perfect for the light table, construction, and fine motor play. The brightly colored pieces are perfect for children to build a variety of creations. This set universally connects with other builders. Includes a sturdy storage container with locking lid. Available in 72 and 150 piece sets. Four building boards included with the 150 piece set only. Smallest block size is 1 1/4".