1.) Made for the professional Supermotard & Motocross racer. 2.) The lightweight high-performance racing chain is the result of innovative metal alloys and the latest manufacturing technology. 3.) MXZ chains - chrome-alloyed steel construction with seamless rollers and bushes, and oversized specially hardened bolts for added stability. 4.) All versions are heat treated by the RK exclusive HIT (Heat Induction Transfer) method. 5.) 420 MXZ High-performance racing chains are among the strongest in their class and have an excellent price / performance ratio with respect to all MX racing chains worldwide!