Great envelope. The only problem I see is the same I see will all envelopes. The sealant does not go far enough to the ends of the envelope. This creates a little packet that has the tendency to open up and I'm sure causes problems with other envelopes getting under this opening and messing up the sorting system. I usually put a piece of tape on each end just to seal more. I don't know if this is a real problem in mail offices but it could be. All envelopes are like this. Every brand. Some are worse. Some envelopes from some manufacturers don't even seal up when you lick the glue type to seal. Those are really bad. Staples are some of the best self seal envelopes.