Everything including bristles are made out of bio-based plastic, which was produced with renewable castor oil instead of limited fossil raw materials (petrochemicals) as in ordinary plastic. Castor oil was chosen as component of the bio-based plastic because it grows in the Mediterranean (in contrast to bio-based plastic made out of sugar cane, which has to be imported from over-seas). Castor oil is a renewable natural product that is produced from the seeds of the Ricinus Communis miracle tree. It’s neither used as food nor as animal feed, and its cultivation therefore does not compete with the areas under cultivation for food.