§ 3631. Applicability; definitions and updates

• (a) This subchapter shall apply with respect to—
  • (1) priority mail;
  • (2) expedited mail;
  • (3) bulk parcel post;
  • (4) bulk international mail; and
  • (5) mailgrams;
• (b) For purposes of this subchapter, the term “costs attributable”, as used with respect to a product, means the direct and indirect postal costs attributable to such product through reliably identified causal relationships.
• (c) Mail matter referred to in subsection (a) shall, for purposes of this subchapter, be considered to have the meaning given to such mail matter under the mail classification schedule.