Get the best results out of your HP printing system. HP Smart technology and chemically-grown toner formulas in HP colour LaserJet print cartridges work with your printer to deliver accurate, consistent colour and reliable, cost-effective performance. Accurate colour, precise image reproduction and crisp, sharp text every time you print. Chemically-grown toner and HP Smart printing system technology deliver consistent results and reliable performance throughout the life of the cartridge. Save time with all-in-one HP 645A LaserJet supplies. HP Smart technology makes automatic adjustments to optimize print quality and enhance reliability. Minimal user intervention saves time, improves productivity and lowers overall printing costs. Enjoy low maintenance, trouble-free printing. HP Smart technology in the toner cartridge and your printer makes HP supplies easy to install and maintain. Receive automatic alerts when a cartridge is low or out. Enjoy convenient, on-line ordering. Warranty: This HP product is warranted to be free from defects in materials and workmanship.