Bikemaster’s upgraded O-ring chain offers durability at a value-price. The chain’s component designs are optimized with computer analysis to provide higher tensile strength. The reinforced roller offers higher impact resistance and longer durability. Its round river head offers superior rigidity over two or four point (quad-staked) riveting. The 520 BMOR chain comes with clip link. Both the 525 and 530 BMOR chain comes with rivet link.