Elastic sweaters are made of all wool. All-Mao Mao clothes have a feature that they shrink when washed. You think the elastic sweater is very thin. You can stretch it with thick cardboard to solve the problem of being too thin for the time being. But when the weather is warm, you won't wear it. After washing, it will become thin. When you wear it again next year, it will still be too thin. Either expand it with cardboard next year, or give it to someone thinner than you. Remember to buy a large size next time you buy a stretch sweater! Have a happy day!