A final rule is a legally binding regulation that has been issued by an executive branch agency after going through a formal process of public notice and comment. It represents the agency's interpretation of a law passed by Congress, and it sets out specific requirements and procedures for carrying out the law. A final rule becomes effective on the date specified in the rule or when published in the Federal Register if no effective date is provided. Once a final rule is in place, it can be enforced through legal action and may be subject to change only through a formal amendment or repeal process.