MICR Toner for HP LaserJet: 4240, 4240n, 4250, 4250dtn, 4250dtnsL, 4250n, 4250tn, 4350, 4350dtn, 4350dtnsL, 4350n, 4350tn Equivalent to the HP Q5942A cartridge. Yields up to 10,000 pages. Specially made for encoding checks. Replaces regular toner with special Magnetic Ink Character Recognition toner. Printing your own encoded checks saves you the expense of ordering pre-encoded checks. All you need is the MICR toner, blank check stock and the MICR font installed on your printer. The iron oxide in the toner allows the magnetic reader sorter at your bank to read the symbols at the bottom of the check