permissible enclosures for fourth-class mail

permissible enclosures for fourth-class mail Sec. 115. Section 4555(a) of title 39, United States Code, is amended— (1) by striking out “and” at the end of clause (9); (2) by striking out the period at the end of clause (10) and inserting in lieu thereof and”; and (3) by adding at the end thereof: “(11) invoices, whether or not also serving as bills, if they relate solely to the matter with which they are mailed.’”.