FST Performance RF500 Silver 4 Micron Rating Replacement Fuel/Water Separator Filter for RPM300/350 Replacement filter element which is totally self-contained and requires no messy and questionable canister cleaning; eliminates cartridge style filter back flushing and totally eliminates any chance of fuel system contamination With the filter sealing system there are no housing seals or gaskets to dig out and no gaskets, o-rings or seals to leak or swell The RF500 unique flow pattern increases filtration efficiency and provides the maximum flow and the heart of the FloMax system Patented filter flows 300 gallons per hour down to 4 microns with a total of 183 square inches of filter media and water capture reservoir Sold individually; made in USA and backed by a full 60 day limited warranty