Buy Knobless Cylinders 4 sets of 10 cylinders varying in height and/or diameter in each set. Each set is in a separate wood box with the lid painted the same color as the cylinders: red, green, yellow and blue. Develop a child's visual perception of dimension. It also provides experiences in comparison, grading and seriation - indirect preparation for mathematics. • Dimensions of Each Wooden Box: 6.5 x 4.5 x 2.75 Inches • Recommended Ages: 4 years and up Buy now: https://kidadvance.com/knobless-cylinders.html