1) An SASE is one 2) Britannica ref 3) Britannica vol 4) Business letter letters 5) Business-letter footnote 6) Cause of an envelope bulge 7) Cover letter letters 8) Cover-letter letters 9) In an env 10) In the env 11) In this env 12) In this pkg 13) It comes in vols 14) It goes in an env 15) It may be a copy of a ck Found on https://www.crosswordclues.com/clue/enc