I bought these envelopes with the hope that I could just peel and stick and not have to worry about licking the envelopes to seal them. Unfortunately they don't really stay closed since the glue is minimal and ineffective at sealing the package. I needed to use packing tape to seal the envelopes. The envelopes are also very thin and could break apart in the mail. If you're going to use them in your home office to file things I would say they're sufficient. But if you need them to you know securely seal a package to put in the mail then definitely turn elsewhere.