The ARB Differential Breather Extension Kit is a supplement for the ARB Differential Breather Kit, which contains enough tubing and components to replace the factory breathers on two drivetrain components and extend those breathers to a high-mounted, single manifold that breathes through an air filter for dusty conditions.  However, the ARB Differential Breather Kit's manifold will accept up to four tubes.  That is where the ARB Differential Breather Extension Kit comes into play. 

The ARB Differential Breather Extension Kit contains eight meters of 8mm polyurethane tubing and four 8mm 1/8 BSP push-in fittings.  This kit will let you extend the breathers on two more drivetrain components and connect all four drivetrain components (such as front axle, gearbox, transfer box, and rear axle) to the ARB Differential Breather Kit's manifold with air filter and have all four drivetrain components breathe through that air filter in dusty conditions. 

Mount the manifold as high on your vehicle as possible, you will go a long away to preventing water ingress into your drivetrain components during wading.  Most will mount the manifold high on the firewall or bulkhead, but note that many of the Camel Trophy vehicles had the breathers extended all the way into the snorkel heads.  The eight meters of 8mm hose contained in this kit will let you extend your breather hoses to such heights on your vehicle.