Genuine OEM Volkswagen drive shaft boot clamp, part number N91213305. This clamp is used to secure the CV joint boot to the axle assembly, preventing grease from escaping and protecting the joint from road debris and moisture. It is positioned on the drive shaft assembly as shown in the diagram. Genuine OEM clamps are engineered to provide the exact tension required to maintain a permanent, leak-free seal under high rotational speeds and extreme temperature fluctuations.