(a) The following requirements for disclosure of metallic weighting are based on, and interpretive of, section 5(a) of the Federal Trade Commisison Act, as amended, and are to be construed as supplementing the fiber identification requirements of the Textile Fiber Products Identification Act and the rules and regulations issued thereunder.

(b) In the case of yarn and fabric containing metallically weighted silk fiber, the fiber identification required by the Textile Fiber Products Identification Act (72 Stat. 1717; 15 U.S.C. 70), and the rules and regulations issued thereunder, shall be immediately accompanied by a clear and non-deceptive disclosure of the fact that the silk fiber present is weighted, with specification of the percentage of the total weight of the silk fiber content in its finished state which the weighting represents: Provided, however, That specification of the percentage shall be subject to a tolerance not exceeding 3 percent when the deviation is not intentional and reasonable effort has been made to determine and accurately state the precise percentage; and, Provided further, That in lieu of a statement of the precise percentage, a maximum percentage may be stated when the precise percentage does not exceed such maximum.

(c) The disclosure of such weighting, in accordance with the above requirements, shall be on the same label on which appears the fiber identification required by the Textile Fiber Products Identification Act and the rules and