What can you say about envelops? Well these are as advertised slightly tinted which prevents prying from trying to read or figure out the contents through the envelop. The adhesive strip adds to the convenience. I don't like licking envelop glue. I use several envelops a week. Boxes of 100 are a perfect quantity.
I have always used Staples privacy tinted number 10 envelopes. They are sturdy and seem to be made of heavier stock than most other envelopes. I trust Staples products.