Renewable Toner 42X 38AX Q5942X Q1338AX MICR Toner Cartridge for Check Printing Compatible with HP LaserJet Printers 4240 4250 4350 Series Lifetime Warranty. We always honor our warranty, even if the Amazon return window has closed. Contact us directly with any questions or issues. RT MICR Cartridge with magnetic toner for check printing OEM #: HP 42X / Q5942X | 38AX / Q1338AX | High Yield: 20k standard pages 60,000 checks @ 3-per page For use in HP LaserJet Printers: 4240n, 4250, 4250n, 4250tn, 4250dtn, 4250dtnsl, 4350, 4350n, 4350tn, 4350dtn, 4350dtnsl RT is the manufacturer of this MICR toner cartridge. The listing of any RT product is not intended to imply any endorsement or direct affiliation with the OEM trademark owner.