1 PK Compatible Q5942A 42A Black Toner Cartridge For HP LaserJet 4240 4240N 4250 one year guarantee Page Yield: 10000 pages If printer does not recognize cartridge, remove the chip from the toner and reinstall the toner into printer. When the error message appears please click "OK" or "ENTER" button. Q5942A 42A Black Toner Compatible with HP LaserJet 4240 4240N 4250