It is a mixture of betel nuts, tobacco, paraffin wax, catechu, and slaked lime. Chewing of betel nut ("Areca catechu") quid has been directly associated to cause oral cancers. "Areca catechu" is grown for its commercially important seed crop, the areca nut. Gambier has been used as a form of catechu for chewing with areca nut. Common names for it include kher, catechu, cachou, cutchtree, black cutch, and black catechu. The extract of "Areca catechu" may be addictive. The base of the shamel is carved out of 'Khair' (acacia catechu) wood. The heartwood, bark, and wood extract (called "catechu") are used in traditional medicine. Senegalia catechu is a deciduous, thorny tree which grows up to in height. Khair trees are used as a raw material for preparation of catechu or kattha. They are particularly skilled in making catechu from Khair trees. Catechin was first isolated from the plant extract catechu, from which it derives its name. It was on these riverbeds that they cultivated catechu and black pepper. There is a hub of small scale Catechu factories.