Examples of combined ratings:
Example: 104-This vehicle when completed will conform to FMVSS No. 104, Windshield Wiping and Washing Systems, if no alterations are made in the windshield wiper components.
Example: 121-This vehicle when completed will conform to FMVSS No. 121, Air Brake Systems, if it does not exceed any of the gross axle weight ratings, if the center of gravity at GVWR is not higher than nine feet above the ground, and if no alterations are made in any brake system component.
49 C.F.R. §568.4