Great for travel, teacher's desks, and for moving between classroom learning centers. Use them as a starter set before introducing other sets. Combine them with other builders or your own unit blocks. Use them in the math center for a quiet and engaging manipulative for a single child. Korxx products are proven to be free of pollutants and sustainable. They consist of special pressed cork material and are free of harmful substances (z.B. Phthalate, dioxins, formaldehyde).