Flex designs and builds products that other companies sell under their own brands, spanning circuit boards, finished devices and the equipment around them. The work covers automotive electronics, medical devices, industrial equipment and the power and cooling hardware that data centres depend on. Contract manufacturing is a scale business with thin margins, so returns come from utilisation, supply chain execution and shifting the mix towards design and engineering work that pays better than assembly alone. Results follow the production plans of its customers, which means revenue can move sharply when a large customer changes volumes.