... Precision roller chain meet or exceed DIN, ANSI,ISO,BS,JS standard, and stand up to the toughest working environment. Our ... Precision roller chain meet or exceed DIN, ANSI,ISO,BS,JS standard, and our chains stand up to the toughest working ... with surface and core 39-45HRCShot peening per the spec 4-Strands B Series 12B Roller Chain Manufacturer