ADF Maintenance Kit for HP 4345,4730 MFP Printers. A Maintenance kit is a preventive measure for HP LaserJet series printers. Through extensive testing, HP engineers have determined that certain printer parts undergo similar wear patterns over time. The HP LaserJet maintenance kit contains replacements for these parts. Although purchasing a maintenance kit is not required, regular insertion of a genuine HP Maintenance kit in an HP LaserJet printer helps eliminate repeat service calls and maximizes paper feed and print quality performance. In addition, maintenance kits are priced substantially lower than purchasing these same parts individually.