Genuine OEM Audi Clutch Master Cylinder, part number 8E1721401AJ. This critical hydraulic component is responsible for converting the mechanical force from the clutch pedal into hydraulic pressure. This pressure is then transmitted to the slave cylinder, facilitating the smooth engagement and disengagement of the clutch. Weighing 0.267 kg and measuring approximately 0.21 m in length, it is engineered for precise fluid displacement and reliable operation. Choosing a genuine OEM clutch master cylinder ensures correct bore diameter, seal integrity, and material compatibility for consistent pedal feel and dependable clutch system performance.