Genuine OEM Audi Chain Tensioner, part number 03C109507BA. This component is responsible for maintaining the correct tension within the engine's timing chain system, ensuring synchronized operation of internal components. It is a critical part of the timing system. The tensioner has dimensions of 0.078m x 0.045m x 0.05m and weighs 0.102 kg. Genuine OEM chain tensioners are vital for engine longevity and performance, as they are manufactured to precise tolerances to prevent chain slack and potential damage.