HP 970 Original Ink Cartridge 56.5-ml Black CN621AEA world leader in ink technology, Hewlett Packard have developed over 100 new inks in the last twenty years. Specially formulated to work in harmony with your machine, HP's DesignJet dye based ink system combines printhead, printhead cleaner and ink cartridge to produce rich, vibrant images and sharp, clear text. This OfficeJet cartridge however is a simple, black affair but it can make a huge difference to the productive nature of your appliances.