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 520MX: The 520MX is a highly loadable chain for the SX and MX range, which is characterized by a extremely high tensile strength. Due to its robust design, the highest loads in the motocross race. - designed for very high loads in the terrain Gold-colored outer pockets, black inner pockets (G & B Gold and Black).