16 C.F.R. § 300.3
(a) The marking of wool products under the Act shall be in the form of a stamp, tag, label or other means of identification, showing and displaying upon the product the required information legibly, conspicuously, and nondeceptively. The information required to be shown and displayed upon the product in the stamp, tag, label, or other mark of identification, shall be that which is required by the Act and the rules and regulations thereunder, including the following:
(b) In disclosing the constituent fibers in information required by the Act and regulations in this part or in any non-required information, no fiber present in the amount of less than 5 percent shall be designated by its generic name or fiber trademark but shall be designated as “other fiber,” except that the percentage of wool or recycled wool shall always be stated, in accordance with section 4(a)(2)(A) of the Act. When more than one of such fibers, other than wool or recycled wool, are present in amounts of less than 5 percent, they shall be designated in the aggregate as “other fibers.” Provided, however, that nothing in this section shall prevent the disclosure of any fiber present in the product which has a clearly established and definite functional significance when present in the amount stated, as for example:
“98% wool 2% nylon.”
[29 FR 6623, May 21, 1964, as amended at 45 FR 44261, July 1, 1980; 50 FR 15105, Apr. 17, 1985; 63 FR 7516, Feb. 13, 1998; 79 FR 32163, June 4, 2014]