DID CHAIN - 520*106 X-RING CHAIN , MADE IN JAPAN DID CHAIN - X-RING VX SUPERIOR STRENGTH D.I.D's #1 VX Series includes the 520VX3 chains to for numerous street and off road motorcycles LONGER WEAR LIFE D.I.D's VX Series boasts a much longer chain life than the VO Series due to the patented X-Ring technology. The 520VX3 has a 32% longer chain life than the 520VO and the 525 and 530VX3 has a 41% longer chain life! PATENTED X-RING The VX chain series showcases the industry-leading, patented X-Ring seal technology, which leads to extended chain life, minimal friction, and overall amazing performance. D.I.D’s PATENTED X-Ring construction reduces friction by twisting between the side plates instead of being squashed. Normal O-Rings and other makers’ modified O-Rings have squashed points that increase friction. The twisting action of the X-Ring disperses the pressure and minimizes power loss. X-Ring is a U.S.A. Registered Trademark of D.I.D; Daido Kogyo Co. Ltd. Japan