Chapter 16. Congressional Mailing Standards 2 U.S. Code §501. House Commission on Congressional Mailing Standards 2 U.S. Code §502. Select Committee on Standards and Conduct of the Senate 2 U.S. Code §503. Official mail of persons entitled to use congressional frank 2 U.S. Code §504. Mass mailings by Senate offices; quarterly statements; publication of summary tabulations 2 U.S. Code §505. Mass mailing of information by Senators under frank; quarterly registration with Secretary of Senate 2 U.S. Code §506. Mass mailing sent by House Members