The S45 BIO is 80% bio-compostable (in periods changing according to humidity and temperature). The PLA material from NatureWorks is a polylactide acid, chemically derived from the fermentation of sugars derived from plants and it is the only product that allows the production of a bio-compostable pen in the transparent version. The pen features on excellent print area on barrel and clip, the Dokumental ink can smooth writing for 2000 meters.