These soap holders are made of scraps from a lumber mill. The zigzag form is designed to minimize contact with your soap, so it dries quickly. The poplar "Zigzag" dishes are made from the fast-growing, sustainable hardwood, the North American poplar. The rounded, beech "Washboard" dishes have ridges on both sides, to maximize airflow and discourage rot, even on the underside of the dish. *Note that the dishmaker recommends alternating between two dishes, to prevent mold/mildew.