... tempering Heat treatment, surface hardening Dear customers, motorcycle roller chain 520 is for motorcycle TRANSMISSION SYSTEM.Roller chain Quality is vital ... ,A5,A66. O-ring chains and xw-chains: 420,428,520,525,530,630 (Racing Chains)7. Leaf chains: LH series8. ... 25NP,35NP,41NP,40NP,50NP10. Coupling chains Model428 428H 420 520 520h 530 etc ItemMotorcycle Roller chain Motorcycle drive chain GearFront ...