The Bendix PR-4 Series 1/4"-18 NPT Supply Port Air Brake Pressure Protection Valve is designed to allow air to be shared between two reservoirs above the closing set of the valve. It is available in a variety of factory pre-set pressure settings. It delays filling one or more reservoirs until the preset pressure in the primary or braking reservoir is reached. This valve has a fixed setting and is made using premium-quality materials for superior durability. It has a maximum operating temperature of 200 °F. This valve is ideal for use in air brake systems and is designed for long-lasting performance. FleetPride is your First Click in Heavy Duty®.