Replacement pads for the Trodat Professional 5211 and 54110 Ink cartridges are easy to change due to clips on sides and click-into-place-mechanism helping to keep clean fingers Water based stamp ink delivers thousands of uniformed and clean impressions. No toxic substances, no acid, no formaldehyde, and no heavy metals Ready-to-use in all climate conditions, the pad stays fresh by drawing moisture from the air Trodat stamp ink is indelible in accordance with DIN ISO 14145-2; it is bleaching, water and light resistant, it cannot be removed without leaving visible traces – no forgery no fraud