The adhesive on the envelopes doesn't hold well if you have more than one sheet of paper in the envelope. If you want to be certain the envelope doesn't open in the mail you need to use tape to close it.
Our company has tried other less expensive envelopes but we keep coming back to these. Easy to peel and seal works good. The price could be better thus the reason for the 4 stars.
I have been purchasing these envelopes for our law firm for years and have never had any issues. I purchased 2 boxes in the store recently the picture on the box shows the old design of the envelopes but in the box the envelopes are different. The quick strip is 1/2 the size and is plain white without the "STAPLES" branding. The strip is very difficult to remove and the stick closure does not hold as well. I printed 40 envelopes before I realized they were inferior to the old design and immediately returned the boxes to the store. Luckily the clerk was able to find 2 boxes of the old style envelopes so I won't have to worry about envelopes for a couple of months. However if Staples does not return to the old style I'll have to find envelopes somewhere else.
Response from StaplesBy March 4, 2018
I’m very sorry the envelopes are no longer working out for you. I have reported the issue to our Staples Brand Group so we can check with our supplier.
They do not stay closed. They will open within 5 minutes of sealing them. This is not acceptable for a company sending confidential information. I cannot recommend these. As the other reviewer stated buy lots of tape too.