RK's 520XRU was designed for professional MotoGP racing. Featuring UW-Ring seals, XRU is a lightweight professional racing chain. The UW seals reduce friction while maintaining optimal horsepower delivery from the start of the race to the end. Developed in collaboration with MotoGP and World Superbike teams to produce the ultimate racing chain. Tensile strength: 9,000 pounds. Max cc rating: 1,000cc. Max horsepower: 265 HP. Weight: 3.44 pounds per 100 links. Max chain width: 18.88 mm. Note: NOT recommended for street use - RACING ONLY.