The Pen and Crossword range of ink cartridges are intended to work with some of Epson’s popular Workforce printers. The T1621 black is filled with DURABrite ink which is ideal for the office setting due to its quick drying nature. Almost instantaneous drying means you can print double sided documents, overwrite them with highlighters or pass around handouts without worrying about smudging or bleed through. If you print high volumes there is a larger alternative to this cartridge; the T1631 Black XL. Both of these options are the same size and fit the same printers but the XL version contains more ink which makes it ideal for small offices with a high demand for printed documents.