.The 520ERV7 is the top-of-the-line racing chain for all types of motorcycle racing, on and off road. Incredible design and utilization of our patented X-Ring seal technology makes the ERV7 a top performing racing chain available. Utilized by factory teams worldwide, the ERV7 is chosen for Superbike racing with teams such as the Fresh N Lean Progressive Yamaha Racing team and the Warhorse Ducati team. Also chosen by the Honda HRC Rally team, team Honda HRC for SX/MX, and SLR Honda competing in the Score International races, Worcs, and NGPC offroad series.