Model and serial numbers The model number and serial number are listed on an identification label located on the inside of the print cartridge door. The serial number contains information about the country/region of origin, revision level, production code, and production number of the printer. The label also contains power rating and regulatory information. Figure 1. HP LaserJet 1150 printer label (220 volt) Figure 2. HP LaserJet 1300 printer label (110 volt) Figure 3. HP LaserJet 1300 printer label (220 volt) ENWW Model and serial numbers 19