Related Clues:

• Env. stuffer
• A check, one might hope: Abbr.
• G.I.'s link with home
• Abbr. at the bottom of a business letter
• S.A.S.E., e.g.
• Armor of interlinked rings
• Postal delivery
• Correspondence
• Env. contents
• Business letter abbr.
• Letter abbr.
• Bottom-of-letter abbr.
• Iron clothes?
• USPS delivery
• SASE, e.g.