This is a genuine OEM replacement part, it is sold individually.
The Fuel Filter is inside of the fuel tank.
Its purpose is to filter out dirt and other debris from contaminating the carburetor.
It will at sometime become clogged and restrict the fuel getting to the carburetor,and will have to be replaced.
We do have an article and video on How to Replace the Fuel Filters in Your Outdoor Power Equipment..
You can see this by going to the front page of our site and clicking on Repair Center.