The electrical and thermal properties of fiber glass fabrics were instrumental in their early acceptance in high temperature electrical insulation. Combined with alkyd varnishes, silicon resins, silicon rubber, PTFE, mica or pressure sensitive adhesives and slit into tapes, these products continue to be used widely in electrical equipment of all kinds Fiber glass fabrics in combination with thermosetting epoxy resins constitute the basic raw material for printed circuit boards, where the thermal, electrical dimensional stability and mechanical property contributions of fiber glass fabrics to the laminate find maximum utilization. Lightweight fiber glass fabrics are used extensively in multilayer printed circuitry, imparting a high degree of dimensional stability to these products as well as to flexible electrical products.