So hard to find large envelops with self seals for a good price. These fit both requirements. I haven't had a problem with them sticking to each other but I'm sure if you were to leave them sitting for a long time or in a warmer humid environment that could be the case.
some envelopes stick together which leaves things to stick to them in the mail and some of the envelopes are not sealec on the bottom so we have to use tape