Put option is also called put option, seller option, put option, put option or elimination option. Put option means that the buyer of the option has the right to "sell" a certain number of the subject matter at the execution price within the validity period of the option contract, but does not undertake the obligation of selling.

After you buy a put option, you can sell the subject matter at the strike price in the future.

Now suppose it is a stock, and the strike price is 60.

When the market price falls in 40 yuan, you can buy shares in 40 yuan/share. After buying, you can sell the option to the seller (the person who sold you the option) at the strike price in 60 yuan. Then your income is 60-40=20 yuan.

You don't have to say more when you get to 80, do you?