Genuine OEM Volkswagen washer, part number N91091501. This flat washer is designed to distribute the load of a threaded fastener across a wider surface area, reducing stress on the surrounding seat assembly components. It is used to prevent damage to mounting points and ensure a secure, vibration-resistant connection. Genuine OEM washers are manufactured to exact dimensions and material specifications, ensuring they do not deform or corrode under the mechanical loads typical of seat adjustment mechanisms.