3 Nonmachinable Letters
3-1 Criteria for Nonmachinable Letters
3-2 Additional Criteria for First-Class Mail Nonmachinable Letters
3-3 Additional Criteria for USPS Marketing Mail Nonmachinable Letters
3-4 Additional Criteria for Periodicals Nonmachinable Letters
3-5 Priority Mail Express and Priority Mail Letters
3-6 Nonmachinable Criteria
3-7 Odd-shaped Items in Paper Envelopes
3-8 Handling, Content, and Extra Service
3-9 Window Envelope
3-10 Green Diamond Border Envelope
