HP Compaq Presario CQ57 Maintenance And Service Manual page 23

Item Component
(3) Part number/Product number (p/n)
(4) Warranty period
(5) Model description
Description
This number provides specific information about the
product's hardware components. The part number helps
a service technician determine what components and
parts are needed.
This number describes the duration of the warranty
period for the computer.
This is the alphanumeric identifier used to locate
documents, drivers, and support for the computer.
Meijer.com
Service tag
15