HP 27X Black LaserJet Ultraprecise Print Toner Cartridge (C4127X): * The HP C4127X LaserJet print cartridge is designed to work with the HP laserjet 4000 and 4050 series printers * Loaded with special features to ensure top printing results * Ultraprecise features include Dual Polymer Toner particles, a Helical RollerDrive, and Magnetic Seals for optimum output and reliability * The HP 27X Toner Cartridge generates a 65 percent higher capacity of 10,000 average page yield for frequent users