Outfit your semi with enhanced control of its air brakes, with the OTR 4" MV-3 Style Manifold Dash Valve with Expertise Built In. To regulate the amount of pressure in the air brake system, this replacement part features an adjustable valve that either blocks or releases compressed air. Fashioned with durable components and a quality construction to ensure long-term reliability. FleetPride is your First Click in Heavy Duty.