1Improved design and ptfe seals +anti rattle rings. 2Made of material, with precise and professional manufacturing, which has long service life, durable to use. 3If you drive a 6 cylinder vehicle 1993-2006 your Vanos (variable valve timing unit) is most likely failing. The O-rings ?tted to the pistons within the Vanos unit wear prematurely because they are constructed of poor quality rubber which is not suited to the elevated temperatures of their location. The seals fail and lead to Vanos unit failure. Your car do not provide replacement seals, they do provide complete Vanos units at vast expense but these again are ?tted with the same poor quality seals that will fail again. 4The Vanos is version of variable valve timing. It advances or retards the intake and exhaust cams to pull more power out of the engine. It works by using oil pressure to move two pistons in or out and those pistons have o-ring seals in them. The OEM seals were made of buna rubber and they degraded over time. The replacement seals are made of fluororubber and shouldn't have the same problem. 5By installing our improved design seals and Ptfe rings you will restore your Vanos unit to full health. Our seals are specifically designed for the environment in which they are fitted, well suited to the vast temperature range of the Vanos unit, constructed from improved materials designed to last. 6Our seals and piston rings have undergone extensive testing and will not deteriorate over time like the OEM part, designed to last the lifetime of your vehicle.