As a board member of a home-owners association it is my responsibility to mail dues notices to each individual home owner via first class mail. To be able to do that efficiently and quickly in a secure envelope that I don't have to lick to seal is a God send. I would recommend these envelopes to any business who needs to mass mail. The time saved and the fact that you know they are securely sealed is a great comfort when efficiency really counts. I was so impressed with the quality and ease of use that I now use them for all my personal mail when I need a #10 envelope.