This front axle ratio valve is a replacement for the front brake circuit on heavy-duty air brake systems. It regulates air pressure delivery to the front wheel brakes to help keep braking balanced across the axle. It is sold as a single unit.Interchanges:289148EM57170FeaturesFront axle ratio valve for air brake systemsPart of the Air Brake Parts product groupSold as a single unit (1 EACH)Tech SpecsProduct Group: Air Brake PartsSell Pack: 1 EACH