At PrinterSupplies.com we specialize in Hewlett Packard. A paper jam kit or known as an HP roller replacement kit is usually done by the printer owner with known as customer self repair. Most people can change the rollers with instructions. We have instructions for 90% of the kits and will be emailed to you. Kits are sold by tray. Tray-1 is the manual feed tray and not everyone uses that tray as often as tray-2 which is the main pull out tray that comes with the printer. Additional trays can be added to certain printers as add on tray's, they are known as tray-3, tray-4, tray-5 and tray-6. Should you need additional information or not sure what to order, please contact us.