Under §73 of the Trademark Act, 15 U.S.C. §1141m, if a holder files an affidavit that meets the requirements of §15 of the Trademark Act, a registered extension of protection to the United States may become "incontestable". The period of continuous use on which an affidavit of incontestability may be based may begin no earlier than the date of issuance of the registered extension of protection, unless the holder owns a prior U.S. registration of the same mark for the same goods/services/collective membership organization. 15 U.S.C. §1141m-n. See TMEP §§1605 et seq. regarding the requirements for an affidavit of incontestability under §15 of the Trademark Act.