Our compatible HP No. 27 Black, No. 56 Black and No. 28 Color Ink Cartridges will meet or exceed OEM (Original Equipment Manufacturer) specifications and high standards of quality and reliability for your HP FAX 1240. Designed to be 100% compatible and interchangeable with OEM cartridges. Using our compatible cartridge does not void the Printer Warranty. All of our cartridges are tested to the highest degree and only the very highest quality parts used in our production process. 100% Satisfaction Guaranteed or your money back.