thirsty buoy / lifebuoy

There is a filter screen on the rim of the swim ring designed this time, through which the seawater can get into the swim ring and be filtered into fresh water. But after reaching some value, it will be saturated, and the seawater can't get into it.
People can take in the water in the ring through the straw which connects to the swim ring, achieving the purpose of water replenishment, thus extending the rescue time.