Section 5(a) of the Stabilization Act of 1942 provided: “No employer shall pay, and no employee shall receive, wages or salaries in contravention of the regulations promulgated by the President under this Act.” (50 TJ.S.C.A. App. § 965.) Executive Order No. 9250, issued pursuant to the authority of the act, provided in part: “1. No increases in wage rates . . . and no decreases in wage rates, shall be authorized unless notice of such increases or decreases shall have been filed with the National War Labor Board, and unless the National War Labor Board has approved such increases or decreases.” (50 TJ.S.C.A. App., p. 315.) Plaintiffs contend that under these provisions the revision of the wage rate without the approval of the board was ineffective and void, so that the old rate remained in full force and effect.