HP Z1 G2-Workstation - Manual (Page 61)

Locating ID labels
To assist in troubleshooting, product, serial, and authentication numbers are available on each
computer.
● All workstations have a serial number (unique for each workstation) and product number. Have
these numbers available when you contact support.
● The Certificate of Authentication (COA) is used only for systems with Windows 7 preinstalled.
● The Genuine Microsoft Label (GML) is used only for systems with Windows 8 preinstalled.
● A service label shows the build ID and Feature Byte strings, which are needed for system board
replacement.
The all-in-one service label can be found in the location shown in the figure below (pull-out card).
Locating ID labels 53