Air Dryer. Designed to collect and remove moisture as well as solid, liquid, and vapor contaminants from the air before entering the air brake system. Consists of a screw-in type desiccant cartridge and a die-cast aluminum end cover, which contains a safety valve, check valve assembly, and a purge valve housing assemblyaristotle. Has three female pipe threaded air connections. Operates alternately between the charge cycle and the purge cycle. Offers ease of serviceability since replaceable assemblies can be serviced without the need to remove the air dryer from the vehicle. Extends the service life of the air brake system. Helps prevent air brake system freeze up, avoid costly downtime, and reduce maintenance costs. Bendix AD-9 Air Brake Dryer The Bendix AD-9 air brake dryer makes sure only clean, dry air gets into the different components of your air brake system. With this product, you dont have to manually drain the reservoirs on a daily basis just to keep your air brake system working at its best.