The icHeader.model tag is of type icUInt32Number (an unsigned 32-bit identifier value according to the ICC specification). The 4 bytes are the identifier used to distinguish various printer models. The identifier must be unique for each model of printer that has identical icHeader.manufacturer tags and correspond to the name that is used/reported by the printer driver. (For a more detailed discussion of how profiles and drivers are paired at run time, see Mapping Color Profiles to Printer Drivers. The deviceModelDescTag value is also read and placed in the registry under the ModelTag key for clarity even though it serves no functional purpose there.