The National Labor Relations Board seeks enforcement of its order that Retail Store Employees Union Local 876 reinstate a former employee, Anna Pennacchini, with back pay. The Board found in an unfair labor practice proceeding that the union qua employer had violated § 8(a)(4) of the National Labor Relations Act ("the Act") by firing Pennacchini in retaliation for her refusal to testify voluntarily for the union in an earlier unfair labor practice proceeding.*fn1 219 NLRB 1188 (1975). Section 8(a)(4) states that it shall be an unfair labor practice for an employer "to discharge or otherwise discriminate against an employee because he has filed charges or given testimony" in an NLRB proceeding. The union petitions for reversal of the Board order on the grounds, inter alia, that the Board's findings are not supported by substantial evidence, that § 8(a)(4) does not protect employees who have refused to offer testimony, that Pennacchini was a "managerial" employee not protected by the Act, and that the reinstatement order constituted an abuse of discretion.