For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

California Proposition 65 WarningRadio/Audio System Description and Operation
The entertainment system on this vehicle may have several different configurations
available to it. To determine the specific configuration of the vehicle, please
see the Service Parts ID Label, and refer to RPO Code List.
Each item in the list below represents topics covered in detail below. ...
Paint Gauges
Paint thickness gauges measure the total thickness of the vehicle finish. It
is important to accurately measure the thickness of the finish on each vehicle as
the thickness of the finish will vary on each vehicle. Use a paint gauge before
the sanding process in order to accurately measure how ...
Roof Front Header Panel Replacement
Removal Procedure
Warning: Refer to Approved Equipment for Collision Repair
Warning.
Note: The roof front header panel is made of Ultra High Strength
Steel and should be replaced only at factory joints. Repairing or sectioning
of this part is not recomme ...