A differential/axle breather serves the important purpose on a 4WD vehicle of venting the air pressure in drivetrain assemblies such as the differential, transmission, and transfer cases. Many drivetrain assemblies are fitted with a breather from the factory. These factory breathers are usually a one-way valve mounted directly to the housing or remotely on a short tube. There are many shortcomings to this style and the ARB Differential Breather Kit is designed to eliminate these by providing a high flow, zero back pressure, zero vacuum breather system. The kit is intended to replace your factory breathers and contains enough fittings and tubing to connect at least two drivetrain assemblies.