Do you know about the differences and benefits of a Z-Ring Chain compared with an O-Ring Chain? The Z-ring has four (4) contact points in contrast to two (2) contact points with the O-ring version. This means higher flexibility and better running characteristics for the Z-ring chain. The spring effect of the Z-ring guarantees consistent and permanent lubrication. This means a significantly longer service life for the Z-ring chain. The Z-ring provides a better seal against penetration by water and dirt. KTM PowerParts P/N: 503.10.800.118/04.