... , and stand up to the toughest working environment. Our Precision roller chain meet or exceed DIN, ANSI,ISO,BS,JS standard ... relations with you in the near future.General Standard for Roller Chain:ROLLERSolid RollerMaterial 1035,1045 or 1050Through harden with surface ... core 39-45HRCShot peening per the spec 4-Strands B Series 12B Roller Chain Manufacturer