The Cylinder Blocks (also called the Knobbed Cylinders) is a classic piece of Montessori material that develops skills in size differentiation, sorting, and hand/eye coordination. The set consists of four blocks each containing ten cylinders of varying lengths and/or diameters. Each block and cylinder is made of solid beechwood with a natural, satin-touch finish, and each cylinder has a large wooden knob attached for a secure and comfortable grip. The cylinders fit precisely within their spaces, but not so snug that they can't be easily removed and re-inserted. The size of each piece in this set corresponds with a piece from the Knobless Cylinders set and the Cylinder Blocks Cards (sold separately). The Rack for Cylinder Blocks makes a great storage and display solution, and the Small Cylinder Blocks and Mini Cylinder Blocks sets are also available.
I'm very picky about my Montessori materials and these are easily comparable to Cylinder Blocks of a much higher cost. I was very pleasantly surprised and pleased with the quality and would highly recommend these for home or classroom.