These envelopes work as described. They are tinted so whatever you put in the envelope cannot be seen from the exterior. And I love the fact that the envelopes are gummed so no licking to seal them. Just pull the tab and press.
For some reason when I run these through my printer and postagemachine the ink does not sink into the paper. This lead to many checks and documents in the mail being lost. A few returned with barely readable addresses because the ink had been smeared all over the place. Use handwriting / pen only. Don't run through your printer or postage machine.