Genuine OEM Audi Antenna Amplifier, part number 4K0035225B. This electronic module is designed to strengthen radio and communication signals, ensuring clear and reliable reception for the vehicle's audio and infotainment systems. It is typically located on the left front side of the vehicle's roof assembly. The amplifier is a compact unit, weighing approximately 0.063 kg and measuring 0.12m in length. Using a genuine OEM amplifier ensures correct signal processing and compatibility with the vehicle's complex electrical architecture, preventing interference and maintaining factory performance.