Set of 300 small cubes (3/4 inch) with grids and knobs that snap together to form imaginative structures. Promotes perceptual and fine motor development and encourages cooperative play. Made of durable, washable plastic in 6 bright, appealing colors, Storage bin with locking lid included. Recommended for 3 years +. EARLY STEM: 3/4 inch cubes are the perfect size for preschoolers to explore early engineering concepts. CUBES SNAP AND LINK: Each cube has 5 faces with 4 x 4 open grid, and one face with 4 knobs. Cubes easily snap together vertically and horizontally to form imaginative structures. PROMOTES PERCEPTUAL AND FINE MOTOR DEVELOPMENT: Preschoolers will feel a real sense of accomplishment as they discover how to fit the knobs into the grids and watch their structure grow bigger with each added cube. ENCOURAGES COOPERATIVE PLAY: Bright colors and interesting cubes invite everyone to join the building fun. 300 colorful cubes mean that there's plenty for several children to play together and build super-cool constructions. DURABLE, SAFE PLASTIC: Cubes are made of durable, washable plastic for years of building fun. Ages 3 and up.