It's the mascara you get with the free gift they offer when you spend some amount on lancome products! It says not for individual sale, so I guess you could say it's a sample size, but I have 2 of these, and they have lasted me for quite some time.
The mascara doesn't say it's waterproof, but I'm currently using one of these, and it stays on great without smudging.. now if you are going out to swim or play high intensity sports on a hot day, then I don't recommend this to wear if you are doing anything that requires getting a lot of water on your eyes or sweat... and Sealed? I don't know that these actually come sealed. But these have never been opened or used though. I can say that!