If I'm being honest, I'd probably call the Laneige "Lip Sleeping Mask" a glorified lip balm. After all, it doesn't do much more than protect and soften lips overnight -- but it does that really well.
I got this as a sample just when I needed it most - in the dead of winter, when my lips were dry and chapped. I've been wearing it every night since, and I've been waking up with soft, smooth lips every morning. I even use it sometimes in the morning as a base under lipstick (especially helpful if I'm going to wearing a matte).
What I love most about this lip product is the texture. It feels a lot like Vaseline, but there is no petrolatum in it. That should be good news to anyone who's sensitive to petroleum jelly - I am, and if I tried to leave Vaseline on my lips overnight, I'd wake up with itching and irritation.
The mask protects as well as a petroleum jelly product, though. Its combination of waxes and butters - plus sodium hyaluronate (hyaluronic acid) - locks in moisture. It also stays put through the night - I typically wake up with a thin film still on my lips.
The jar comes with a cute little rubber spatula (which I immediately threw in a drawer). A little goes a long way, so I expect my full-sized jar to last until next winter (in fact I still have the sample jar - it lives in my travel kit).