The handle of a toothbrush burns fewer calories when incinerated after use, and emits less CO2 than ordinary resin. It is a sustainable toothbrush because it is made of a material that is a blend of polylactic acid resin and fine bamboo powder, and uses plant materials that grow in one year. The bamboo grown in Iga City, Mie Prefecture is managed in-house, and all of it is carefully made at a factory in Japan. Due to the characteristics of natural materials, the handle part decomposes and loses strength, so we have set the industry's first quality retention period of two years. The packaging uses "bamboo paper" made from 100% Japan bamboo. [About castor resin hair] We use 100% plant resin derived from castor beans harvested from castor seeds. Castor oil has also been used as a cosmetic and soap since ancient times. It is a colorless and transparent bristle that is as supple as petroleum-based nylon, and it is characterized by the fact that it does not change the feeling of use. It is also recommended for vegans. * Castor resin hair is not biodegradable.