Genuine OEM Audi Clutch Master Cylinder, part number 420721388. This component is vital for manual transmission vehicles, converting the mechanical force from the clutch pedal into hydraulic pressure to actuate the clutch. It is typically located on the firewall, connected to the clutch pedal and the hydraulic line leading to the slave cylinder. Constructed from durable materials, this master cylinder weighs approximately 0.218 kg and measures 0.27m in length. Using a genuine OEM clutch master cylinder ensures correct hydraulic pressure, precise pedal feel, and long-term reliability for the entire clutch system.