If you have electronic fuel injection, you should run a coarse pre-filter (FF-2, 90 micron) before the fuel pump, and a fine post filter (FF-1, 10 micron) after the fuel pump. If you are running mechanical fuel injection, you will only need the FF-2 pre-filter.
The FF-2 pre-filter is a 90 micron stainless mesh filter that will keep large debris from entering and damaging your fuel pump. The FF-1 post-filter is a 10 micron, high surface area, high pressure filter that will keep fine particulates out of your electronic fuel injectors, if so equipped.
Mechanical Injection Systems Require Only a Pre Filter