16 C.F.R. § 259.3
To prevent deceptive claims, qualifications and disclosures should be clear, prominent, and understandable. To make disclosures clear and prominent, marketers should use plain language and sufficiently large type for a person to see and understand them, should place disclosures in close proximity to the qualified claim, and should avoid making inconsistent statements or using distracting elements that could undercut or contradict the disclosure. The disclosures should also appear in the same format as the claim. For example, for television advertisements, if the fuel economy claim appears in the video, the disclosure recommended by this Guide should appear in the visual format; if the fuel economy claim is audio, the disclosure should be in audio.
16 C.F.R. §259.3