REASONS TO BUY THE GEAR: 1. The "Flag" gear resets the printer and tells it when a new cartridge has been installed. 2. A new cartridge prints light when first installed . When the flag gear resets the printers toner low message, it will print at a higher voltage to make up for the low voltage on the new toner cartridge. This increases your print quality and as the cartridges page count increases the voltage slowly diminishes. This ensures perfect quality printing throughout the life of the cartridge until the toner is low and is refilled. 3. The flag gear resets the "Toner End Life" message and will make the printer think you just installed a new cartridge which will reset the voltages to begin a new "cartridge cycle"..