These charcoal sticks are made of grape vines that have been burnt to a specific hardness. Unlike compressed charcoal, vine and willow charcoal doesn't use a binding agent which results in clean erasing.

Artists' charcoal is a form of dry art medium made of finely ground organic materials that are held together by a gum or wax binder or produced without the use of binders by eliminating the oxygen inside the material during the production process.