Related Clues:

• Check within, say?: Abbr
• Inside, for short
• Letters followed by a colon
• Start of a memo heading
• Business env. letters
• Postal abbr
• Env. stuffing
• S.A.S.E., e.g.: Abbr
• Routing abbr
• Env. within an env., perhaps
• Pkg. insert
• Postal letters
• Fax abbr
• Memo heads-up
• Meant for, for short