Generic Compatible Toner Cartridge Replacement for HP C3903 -4PK Alternative to OEM, comes with ONE YEAR WARRANTY from the date of purchase against manufacturer defects. Page Yield: Black 4000 pages at 5% coverage on Letter/A4 paper. This replacement Toner cartridge is built to ISO9001 and ISO14001 Factory Standards. Compatible with HP LaserJet 5P, 5MP, 6P, 6MP, 6PSE, 6PXI