The bowls are made of black walnut, cherry and maple. These are small serving bowls that vary in size from a maximum of 6 inches wide and from 3 to 6 inches high, They are finished in hand rubbed polyurethane. Which is food safe after exposure to air for 30 days or more. The size of the bowls are determined in large part by the size of the piece of wood I have. Large kiln dried pieces of wood that are affordable are not easy to find.