Quick view RK 520SO - 120 Link Gold O-Ring Chain & Spring Link MSRP: £56.22 RK 520SO is a Classic ! The best choice if you are looking for an economical chain for motorcycle from 250cc to 400cc. RK utilizes Nitrite Butadiene O-Rings to seal in lubrication and deliver smooth power with minimal loss of horsepower. Add to Wish List Add to My Wish List Create New Wish List