RK 520So O-Ring Chain RK's SO series chains are designed with a traditional round O-ring, catering to low- to mid-range CC motorcycles needing factory sealed chains. Ideal for motorcycles up to 400cc, the 520So chain is versatile for both on and off-road use. It features an O-ring made from Nitrite Butadiene, effectively sealing in lubrication while minimizing seal ring drag and horsepower loss. Features: Traditional round O-ring design is a convenient blend of performance and affordability Nitrite Butadiene seal seals in lubrication to deliver smooth power and minimal drag Clip type master link included Specifications: Tensile strength: 6,900 lbs Max CC rating: 400cc (street and offroad) Max horsepower: 60