This is a 2-pack of premium compatible Black Laser Toner Cartridges for use in Xerox 5441, 5451, 5665, 5837, 5845, 5855 printers. MTI © toner cartridges are engineered to exceed industry standards of high yield and exceptional quality, and guaranteed to perform with Xerox printers. Every cartridge is factory tested and ISO approved. We offer an exclusive 30-day customer satisfaction guarantee and 1-year Manufacturer Warranty. Our dedicated customer care staff is available 9 a.m. to 7 p.m, Monday through Saturday, to answer any questions and provide technical support.