Century 974W25 Installation, Operation, Maintenance, Parts page 23

Section II - SPECIFICATIONS
2.1 CERTIFICATION LABEL
Federal law requires that the final stage manufacturer, i.e., that
person or company installing new equipment on a new chassis,
must certify the completed vehicle by obtaining, completing and
affixing to the door post on the driver's side of the vehicle, a
CERTIFICATION LABEL similar to the one shown. See Figure 2.1.
FIGURE 2.1
II-1