WATER-BLOCK spin-on canister absorbs water from gasoline and diesel fuel, and filters microscopic particles (10 microns) of rust, sand, dirt, scale and lint. Restricts fuel flow as water is absorbed, signaling the need for a canister change. Also can be used with biodiesel blends up to 20%. Zinc die-cast top cap with 1 inch NPT pipe fittings. Maximum recommended working conditions 50 PSI and/or 12 gpm.