The "heavily gummed" adhesive doesn't stick; I need to tape these envelopes to keep them shut. The metal clasp doesn't always line up with the punch holes in the envelope flap either. I was unaware when I purchased these that the postal service charges $.20 extra per envelope when those metal clasps are present and have to pull each one off now. Definitely go for a peel & stick envelope - this one is a pain in the neck.