RK520 EXW Gold XW-Ring 120L Chain .
There are many chain manufacturers in the motorcycle industry but most (including some Japanese manufacturers) only offer a single type of sealing ring, using a "one type fits all approach" which is used on all their drive chains.
This can be inefficient depending on the intended use. .
Different types of seals for different applications maximises efficiency and performance
RK currently has FIVE types of sealed-ring chains. Each has its own features and benefits.
 
O ring and RX Rings came first. Each a great product in their own right and broadly similar to the competition's current offerings.
After several years of development, RK added the XW range of sealed chains to radically improve chain life and performance.
As racing expanded into several different genres, RK also added the ultra thin U-Ring and UW-Ring sealed chains.
Each seal type is specifically designed for a particular use to provide the ultimate in rotating efficiency with minimum friction, while providing a longer chain life.
Do not compromise: Maximise the motorcycle's performance by fitting RK chain. Mark Marquez does and he does pretty well...
EXW is specifically designed for ATV/Off-Road vehicles and is the best high-speed, extreme heat, off-road performance chain available. EXW chains feature XW-Ring seals to better survive the abrasive conditions that exist in hostile off-road conditions.