DID is an OEM of many Japanese and European brands. Leading racing teams in the Road and off-road sports rely on the technology of DID. DID 428VX: The development of the 428VX is based on the long - term experiences of DID in the MotoGP and fulfills the highest demands through the use of the patented X-rings. Compared to the O-ring equipped V-series, the 428VX has a higher strength and a higher wear resistance. - high durability and low friction due to patented X-ring