Compatible with: HP Laserjet Enterprise 600 M601dn, 600 M602dn, 600 M602n, 600 M603dn, 600 M603n, 600 M603xh, M4555f, M4555h Compatible Replacements Included: 4 pack CE390X black HP 90X Toner Cartridges High Yield Delivers 24,000 pages just like the original HP90X compatible toner cartridge Average cartridge Page Yield* in accordance with ISO IEC 24711. *at 5% coverage (ISO/IEC standard) This is the high yield version of HP compatible toner cartridge 90X Please contact us first with any product issues. We want all of our customers to be happy because happiness matters.