Genuine OEM Volkswagen Reduction Agent Tank, part number 561131878B. This tank stores the reduction agent, such as AdBlue, which is used in selective catalytic reduction (SCR) systems to reduce NOx emissions. It is located in the SCR system assembly. This part weighs 2.59 kg and has dimensions of 0.54m x 0.46m x 0.23m. Genuine OEM tanks are manufactured to precise specifications for optimal performance and longevity in emission control systems.