Air dryers remove moisture from compressed air systems, primarily utilized in heavy-duty vehicles with air brakes. These components employ desiccant technology to cool and filter air, preventing brake line corrosion and ice formation. Integral components include a housing, desiccant cartridge, check valves, and often a modulating valve to control air delivery. Functionality is critical for consistent brake performance and system longevity, as moisture compromises pneumatic component operation. Regular maintenance involves desiccant cartridge replacement based on mileage or air consumption.