BikeMaster 525BMXR Series 120 Length Chain Each refined component designed with computer analysis provides higher tensile strength Specially controlled heat treatment means tougher material, more durability Q4 seal ring and reinforced pin and roller provide superior wear resistance, higher impact resistance and fatigue strength Q4 seal ring offers less friction, which leads to less power loss -- almost half of that of standard O-ring chain Round rivet head offers superior rigidity over 2 or 4-point (quad-staked) riveting