The Bendix® AD-9si® air dryer is a high-efficiency air dryer designed to collect and remove moisture, oil vapor, and solid contaminants from a heavy-duty commercial vehicle's air system. It is an evolution of the industry-standard AD-9® and serves as a direct, more efficient alternative to the Bendix® AD-IP® or competitors like the WABCO SS1200. The AD-9si includes a spin-on style cartridge for easy servicing, and most include a fully integrated governor to control air system charging.