16 CFR § 20.1 - Deception generally.
(a) It is unfair or deceptive to represent, directly or by implication, that any industry product is new or unused when such is not the fact, or to misrepresent the current condition, or extent of previous use, reconstruction, or repair of any industry product.
(b) It is unfair or deceptive to offer for sale or sell any industry product without disclosing, clearly and conspicuously, in advertising, in promotional literature, on invoices, and on the product's packaging that the item is an industry product. Additionally, it is unfair or deceptive to offer for sale or to sell any industry product that appears new or unused without disclosing on the product itself that it is an industry product, using appropriate descriptive terms with sufficient permanency to remain visible for a reasonable time after installation. Examples of appropriate descriptive terms include, but are not limited to “Used,” “Secondhand,” “Repaired,” “Relined,” “Reconditioned,” “Rebuilt,” or “Remanufactured.” If the term “recycled” is used, it should be used in a manner consistent with the requirements for that term set forth in the Guides for the Use of Environmental Marketing Claims, 16 CFR 260.7(e). On invoices to the trade only, the disclosure may be by use of any number, mark, or other symbol that is clearly understood by industry members as meaning that the part so marked on the invoices is not new.
(c) It is unfair or deceptive to place any means or instrumentality in the hands of others so that they may mislead consumers as to the previous use of industry products.