The IPC-4412C covers the requirements for reinforcements woven from "E"glass yarn. These reinforcements are used in the production of prepregs, some of which are pressed into laminates. These prepregs and laminates are the base materials for rigid and mulitlayer printed boards. The IPC-4412C standard contains tables which describe each fabriic style in detail including the yarn used, the number of yarns per unit area, the basis weight and the thickness. The IPC-4412C standard also includes the quality assurance aspects of these strategic building blocks for base materials.