Compatible with: HP LaserJet: 4000, 4000n, 4000se, 4000t, 4000tn, 4050, 4050 usb-mac, 4050n, 4050se, 4050t & 4050tn Professionally remanufactured by LD Products Page Yield* Per Cartridge: 10,000* For best results, store in a cool, dry place. Use within 3 years of purchase for optimal performance. *Average cartridge Page Yield* in accordance with ISO 19752. *at 5% coverage (ISO/IEC standard) All LD compatible and remanufactured cartridges are quality tested to ensure long-lasting use and bold, vivid print on every page