As the name suggests, these manufacturers work on contracts and support OEMs. They can partially or wholly manufacture products based on OEM requirements. It is quite common to see CEMs in oil, gas, defense, computing, and other mission-critical industries as they support OEMs. Some industries have stringent requirements, and sometimes OEMs are unable to meet them single-handedly due to a lack of resources, budget or investment. This is when they partner with CEMs who may possess advanced industry certifications that comply with industry standards. Many CEMs make huge technology investments to meet the changing customer requirements, which is an advantage for OEMs. A CEM may serve several industries at a time, making them dynamic. One of the brilliant examples of CEMs are PCB assembly services and electronic assemblies. Some PCB CEMs can serve multiple industries like medical and healthcare, automotive, military and defense, and so on.