Genuine OEM Audi Coolant Tank, part number 8D0121403L. This reservoir is a vital part of the engine cooling system, designed to store excess engine coolant and allow for expansion and contraction. Constructed from durable translucent white plastic, it measures 0.305 m in length, 0.24 m in width, 0.14 m in height, and weighs 0.609 kg. This genuine OEM tank ensures proper fluid levels and pressure regulation, critical for maintaining optimal engine temperature and preventing overheating.