"Look inside" abbr

• S.A.S.E., e.g
• Steno's abbr.
• Abbr. at the bottom of an application
• Cover-letter letters
• Ref. wd
• S.A.S.E., e.g.: Abbr
• Bottom-of-business-letter notation
• "There's something else in this envelope": Abbr
• Env. extra

Wiktionary Word definitions in Wiktionary
abbr. enclosure (qualifier indicating that a letter is accompanied by further material English)