There are many ways to try to keep lettuce nice for several days in the 'fridge. When I buy "floppy greens," I like to get them in the plastic clamshells if I'm going to be dipping out of it over the week. Many years ago, I had a Tupperware brand Iceberg lettuce bowl. It was rounded, with a domed lid that snapped on over the top. It was ok, but it was sort of tall, and didn't seem to fit well in some of the shelves, plus you couldn't stick anything on top of it. And since the lettuce went down in the bowl, you always felt you had to wash it after use, even if it seemed clean. It was expensive.
Sometimes I use plastic twist-tie "bread sacks" for my cleaned lettuce. But a head of iceberg is just a bit too big, and sliding romain in and out isn't as nice as all that. There is always some moisture, and you don't want the leaves lying in that.
And then I had the serendipity of finishing the last piece of a grocery store bakery cake at the same time I was looking for something to put my head of lettuce in.
I'm telling you, it couldn't be more perfect! The groves in the bottom piece collect moisture and keep it off the leaves. It's like a little terrarium, keeping the atmosphere damp enough to keep the leaves crisp. There seems to be a lot less browning of the cut ends too. The size is perfect, the lid snaps on securely enough, but pops right off when you work it. You can stash a small plate on top if you need to, and the dome never touches the lettuce inside. And it's free, if you buy a cake! A good reason to buy cake. If you need one.