Our Precision roller chain meet or exceed DIN, ANSI,ISO,BS,JS standard, ... stand up to the toughest working environment. Our Precision roller chain meet or exceed DIN, ANSI,ISO,BS,JS standard, ... with you in the near future.General Standard for Roller Chain:ROLLERSolid RollerMaterial 1035,1045 or 1050Through harden with surface and ... peening per the spec 4-Strands B Series 12B Roller Chain Manufacturer