Duration.
Section 12
SEC. 12. Duration.—Each certificate of registration shall remain in force for twenty years: Provided, That registrations under the provisions of this Act shall be cancelled by the Director, unless within one year following the fifth, tenth and fifteenth anniversaries, of the date of issue of the certificate of registration, the registrant shall file in the Patent Office an affidavit showing that the mark or trade-name is still in use or showing that its non-use is due to special circumstances which excuse such non-use and is not due to any intention to abandon the same, and pay the required fee. The Director shall notify the registrant who files the above-prescribed affidavits of his acceptance or refusal thereof and, if a refusal, the reasons therefor.