That is called the inlet strainer.
Save your money. Get a Camco "Blow out" adapter and use an air compressor to blow the water out of the lines.. Do this like 5-10 times waiting a few mintues between blows (All faucets open on at least the initial blow) then use "Pink Stuff" in drains and toilets only.
Come spring.. Folks who use RV-Antifreeze in the fresh system have to get rid of all that **** and the taste it leaves behind.
Folks who use Air just sanatize (Everyone must do that)
One pass with Bleach water
One with Bicabornate of Soda (Baking soda)
One partial rinse
Job done.
