Children will have great fun with this construction and early learning manipulative. Ideal for developing fine motor skills and for counting, sorting, and creative design. Set includes 36 plastic pebbles in 6 sizes and 6 colors and 20 double-sided activity cards measuring 6.75” x 4.50” in a sturdy plastic container. Pebbles measure largest 3.25” x 2” x .5” to smallest 1” x .75” x .25”.