O-ring chain offers high durability. Component designs, optimized with computer analysis, provide higher tensile strength. Specially controlled heat treatment means tougher material. Reinforced roller offers higher impact resistance and longer durability. Finest crafted components assisted with special seal ring with factory grease and "round rivet heads" provide superior rigidity. High tensile steels are used throughout the chain components - larger pins means loads are spread out over wider area, resulting in longer life and more strength. Specifically controlled heat treatment means tougher material and more durability. Comes with rivet link. Made in Japan