Genuine OEM Volkswagen Roller Rocker Arm, part number 0XW109417. A roller rocker arm is part of the valve train that pivots on a shaft and transmits the motion from the camshaft to the valve. This part is located at position 17 in the cylinder head assembly. It weighs 0.062 kg. Genuine OEM roller rocker arms are crucial for maintaining precise valve lift and duration, ensuring optimal engine performance and longevity.