The cord build inside a conveyor belt steel cord carcass is decided long before the belt reaches site, and it fixes how the belt stretches, how much take-up travel the project needs and how much strength a splice can keep. This article works through the cord construction codes buyers see on a data sheet, how cord diameter and pitch produce the rated strength figure, how bonding rubber affects pull-out, and why two belts of the same strength class behave differently on the same conveyor. It also covers the early signals that a cord layer is in trouble and the checks worth doing before accepting a shipment.