It is head lettuce, also called lettuce. It is crisper and tenderer than the big leaf lettuce currently sold in the market. It is very suitable for salads. It is also rich in nutrients and contains a lot of vitamins, but the taste is a bit different. It's a little bitter, so it's suitable to add Thousand Island Salad Dressing to increase the flavor. It is sold in the market. Of course, you have to go to a large supermarket or market. There are stores that specialize in this kind of dishes. If you just haven't noticed it, you can ask.