Quality Assurance?Our products have a guaranteed shelf life of 2 years. In the event that you are unsatisfied with your purchase, we will provide a full refund or complimentary replacement. Please don't hesitate to reach out if you need any assistance or have further inquiries. Certificates?Jettruemedia Ink Cartridge is ISO9001, ISO14001, CE, RoHS, REACH and STCMC certified. Our exclusive formulated ink ensures that prints are long-lasting and vibrant in colour. Invest in quality with our range of cartridges for reliability at an affordable price. High Page Yield?The 970XL black cartridge and the 971XL color cartridges offer impressive page yields--up to 9,200 pages for 970XL black, and up to 6,600 pages for 971XL each color (At 5% coverage of A4). This helps save you money on your daily printing needs. 4-PACK?The ink cartridge of 970XL Black , 971XL Cyan, 971XL Magenta and 971XL Yellow is designed for use with a variety of HP officejet printers. Each original ink cartridge is individually packaged and vacuum packed to prevent leakage during shipping and storage. For Printer?Thanks to the latest chip, it perfectly compatible with your printers HP OfficeJet Pro X451dn X451dw X476dn X476dw X551dw X576dw. It is easy and safe to use.