Vortex Racing EK 525 SRX2 Screw Master 130 Links- NaturalThe EK 525 SRX2 Series Chains incorporate advanced QX rings that significantly outperform traditional O ring chains. Laboratory tests have shown that QX rings reduce friction by 40 percent, resulting in up to 50 percent longer lifespan compared to standard O ring chains. Weight saving holes are drilled into every other chain link to minimize rotating mass without compromising strength, delivering more horsepower to the rear wheel and improving