BIS Certification For Double-pitch precision roller chains and sprockets for transmission and conveyors BIS Certified for Double-Pitch Precision Roller chains And Sprockets Power Transmission And Conveyors. The Bureau of Indian Standards (BIS) have prepared IS 15509:2017 standard on requirements of double-pitch precision roller chains and sprockets used in transmission and conveyor systems. These chains and sprockets are suitable for industrial applications in many sectors. The specification will determine grade and class according to dimensions, materials, mechanical properties and performance to ensure that it can withstand usage. The manufacturers of double-pitch precision roller chains and sprockets would now need to have BIS certification for sale in Indian market. This certificate ensures that they conform with the safety, quality and performance standards established by BIS. All such certified products shall also be marked with the ISI Mark which will be indicative of trust, dependence and quality assurance.