REFURBISHED HP MAINTENANCE KIT, comes with a DOA Warranty against defects. These units are refurbished with the best parts available,and all rollers are new in box. At ORION we take extra special care in testing all of our units as to make sure our customers have no complications, or malfunctions. We value your business and would like to continue to serve your printer technology needs. For HP laserjets 4000 and 4050 series printers, Hewlett Packard recommends the installation of a maintenance kit after every 200,000 pages printed. This is a rough estimate and you may need to install a maintenance kit far sooner than that depending on printing conditions and if the printer has been previously serviced with low quality aftermarket parts. Brand: HP, Model: C4118-67910