WATER-BLOCK filter removes water from gasoline and diesel fuel. Water-absorbing polymers trap water, restricting fuel flow when it is time to replace the element. Also removes microscopic particles (15 microns) of rust, sand, dirt, scale and lint. Also compatible with biodiesel blends up to 20%. Note: When used with fuel containing alcohol, the water-absorbing feature is disabled. Zinc die-cast top cap with 3/4 inch NPT pipe fittings. See-Thru bowl allows for visual monitoring of fuel flow. Working pressure up to 150 PSI and flows up to 5 gpm (gravity fed) at 24 inch head.