Great for travel, teacher's desks, and for moving between classroom learning centers,this mini set of coloful Korxx cork blocks is one of our favorites! 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. They even float. 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).