025 Series fuel prefilters are the first line of defense in protecting against engine damage by keeping fuel clean and dry. These small strainers/prefilters feature a heavy-duty die-cast aluminum mounting head, a 250 micron cleanable nylon mesh screen (or 10 micron Aquabloc filter), and a reusable see-thru water and sediment collection bowl. Aquabloc is Racor's high-efficiency filtration media. It is waterproof and rustproof and incorporates pleat-spacing corrugations and a graduated pore structure to increase dirt-holding capacity and extend filter life