; and (C) the gross income of the employer. . (b) Conforming amendments Section 10(b) of the National Labor Relations Act ( 29 U.S.C. 160(b) ) is amended— (1) by striking six months and inserting 180 days ; and (2) by striking the six-month period and inserting the 180-day period . 110. Limitations on the right to strike Section 13 of the National Labor Relations Act ( 29 U.S.C. 163 ) is amended by striking the period at the end and inserting the following: : Provided, That the duration, scope, frequency, or intermittence of any strike or strikes shall not render such strike or strikes unprotected or prohibited. . 111. Fair share agreements permitted Section 14(b) of the National Labor Relations Act ( 29 U.S.C. 164(b) ) is amended by striking the period at the end and inserting the following: : Provided, That collective bargaining agreements providing that all employees in a bargaining unit shall contribute fees to a labor organization for the cost of representation, collective bargaining, contract enforcement, and related expenditures as a condition of employment shall be valid and enforceable notwithstanding any State or Territorial law. . II Amendments to the Labor Management Relations Act, 1947 and the Labor-Management Reporting and Disclosure Act of 1959 201. Conforming amendments to the Labor Management Relations Act, 1947 The Labor Management Relations Act, 1947 is amended— (1) in section 213(a) ( 29 U.S.C. 183(a) ), by striking clause (A) of the last sentence of section 8(d) (which is required by clause (3) of such section 8(d)), or within 10 days after the notice under clause (B) and inserting section 8(d)(2)(A) of the National Labor Relations Act (which is required by section 8(d)(1)(C) of such Act), or within 10 days after the notice under section 8(d)(2)(B) of such Act