Hand Eye Coordination & Grasping Practice for Toddlers
"Crossing the midline" is a concept in a lot of toddler equipment that you can see clearly from the equipment itself. Look for the midpoint in the dowel and see how the relationship between the objects on the dowel and the arrangement interact. Your child will experiment with this relationship as he or she arranges all of the discs on this particular dowel. Since this is a horizontal dowel, your child will need to carefully push the discs past the midline to fit all of them onto the dowel, unlike the vertical dowel where the cubes go to the base by themselves.
One key feature of Montessori equipment is that it is well-crafted. Everything balances, stands, and performs its function flawlessly. If you find yourself looking at material that is not steady or does not fit well together (e.g. the lid does not close completely or the dowels are different sizes), don't buy it!
The easiest way to create a good DIY project out of this concept is to attach a vertical dowel to a stand and find a series of large symetrical round or square beads of the same color to use as disks. Of course, if you are good with woodworking, a horizontal and vertical dowel set would be great.