Buy insurance for the price of your crypto going down

We will purchase for you the right to sell your crypto at a certain strike price within a certain time period
Let's consider the following example of insurance for the price of ETH going down:
Strike: 3 600 USD
Сost: 300 USD
This offer means that you pay 300 USD now to get the right to sell 1 ETH for 3600 USD on December 1
Let's say the price went to
01.12 = 3 000 USD
This means our profit is
3 600 - 300 - 3 000 = 300 USD