Coil bobbins, namely, bobbins about which electric wire coils are formed for use in electrical equipment; potting forms for forming battery cases, namely, boxes for receiving the electrical components of batteries and a non conductive potting material; capacitor cans, namely, containers for receiving and enclosing the electrical capacitors; electrical instrument housings, namely, enclosures for enclosing and supporting electric connectors and circuit boards; circuit boxes, namely, boxes for enclosing the electrical circuit components of instruments; circuit board stiffeners, namely, channels resiliently engageable on edges of circuit boards for increasing strength of circuit boards; circuit card guides, namely, U-shaped channels resiliently engageable on edges of electrical circuit cards for guiding the circuit cards into electrical connectors on an electrical apparatus; boxes an channels for surrounding and protecting electrical connectors mounted on a circuit board; and structural supports for electrical components on circuit boards, all formed from fiberglass, epoxy and fiberglass/epoxy laminations; EMI/RFI shields formed from metallic foil laminated to nonconductive substrates, namely, enclosures for surrounding electrical components for preventing electro-magnetic interference and ratio frequency interference