This compatible DR233CL (DR-233CL) drum unit is designed for use with HL3210CW, DCP-L3551, MFC-L3710CW, and MFC-L3770CDW printers.The package includes one DR-233CL drum unit.Cartridge number: B-DR233CL.OEM model reference: DR233CL.Estimated page yield: 12, 000 pages.Shelf life: 24 months.Replace the drum when the printer displays a 'Replace Drum' message, or when the drum or photoreceptor drum indicator lights up red or flashes yellow.Replacement is also recommended if printouts show light color, black streaks, vertical thick lines, or repeated vertical patterns such as sets of dots, lines, or other consistent markings.