Related Clues:

• Ltr. extra
• It's put in an env.
• In this env.
• Something besides the ltr.
• Abbr. on a business letter, perhaps
• An SASE may accompany one
• Mailed doc.
• RSVP card, e.g.
• Common pg. size
• 44-Down and the like: Abbr.
• Business letter letters
• Vanna revelation: abbr.
• Ltr. add-in
• Init.
• One photocopier tray: Abbr.