Material : Wood Dimension : 18" x 12" x 3" Set of 4 Knob Cylinders Used in montessori and pre-schools Fun and educational Durable and safe This set of ten knobbed cylinders descending in diameter, descending in height and a block with slots is for inserting cylinder in correct slot. Playing with this game enhances visual discrimination, observation, concentration, eye hand coordination and provides first hand experience of size grading and matching with identical slot. Brand No Brand SKU 100283749_NP-1020545524