Roller chains consist of a strand of overlapping links with intersecting rollers that engage with the teeth of a compatible sprocket to transmit power between rotational shafts. They provide a more precise and controlled drive system over belts because they will not slip or wear. ANSI standard roller chains meet ANSI/ASME manufacturing specifications. British standard roller chains meet manufacturing specifications set by the International Standards Organization metric dimensions (ISO 606), British Standard (BS 228), and DIN 8187. Conveyor roller chains transport loads at low to moderate speeds over longer distances. Leaf chains install onto flat face pulleys, not sprockets, and are suitable for low-speed pulling, lifting, and balancing of heavy loads. Plastic roller chains do not require lubrication and prevent scratching of products in conveying applications.