Product Details: The Bendix PR-2 Series 1/4"-18 NPT Supply Port Air Brake Pressure Protection Valve is an essential component for any vehicle. This valve is available in a variety of factory pre-set pressure settings. It is designed to delay filling one or more reservoirs until the preset pressure in the primary or braking reservoir is reached. The PR-2 pressure protection valve has a fixed setting and uses premium-quality materials for superior durability and performance. It automatically isolates pressure from the brake system during a sudden pressure loss and allows air to be shared between two reservoirs above the close setting of the valve. FleetPride is your First Click in Heavy Duty®.