A1 Envelopes (3 5/8 in x 5 1/8 in) - Response envelopes

Exploring A1 (4bar) envelopes

A1 Envelope Dimensions: 3.625" x 5.125" (3 5/8 in x 5 1/8 in). Suggested enclosure dimension: 3.475" x 4.875" -This is the smallest member of our Announcement Envelopes... many times referred to as Response Envelopes, 4Bar Envelopes or Wallet Envelopes. This is the smallest announcement envelope allowed by the Postal service. (Have questions about envelope sizes, visit our envelope help page)