Available for Freightliner FLD 120 and Classic 1988 up to present models, pre-filter keeps debris particles – rubber, dirt, sand, grain chaff, etc – as small as .005 in. from clogging pleats of air filter element. Product thus extends filter service/life and can be used repeatedly by being cleaned with soap and water. Constructed with 1/8 in. thick ABS plastic, pre-filter features constructed polyester mesh with uniform micron openings and is treated with hydrophobic process.