Hides contents. Seals well and with ease and didn't wrinkle at all when put through my laser printer. Also (due to my forgetfulness) I found that if you need to re-open it if you do it within a minute or two and are very careful and slow you can open it (in case you forgot to put something in like I did) and re-seal it cleanly.....Wait too long though and you'll likely have to tear it open. Good envelopes.