IPC 4202B provides comprehensive data to help users more easily determine both material capability and compatibility for flexible base dielectric materials for manufacture of flexible printed boards. It includes flexible base material specification sheets that have been updated with the newest properties for the specification material types. It establishes the most current classification system, qualification and quality conformance requirements, including high frequency dielectric properties. A new specification sheet for an adhesive fluorocarbon film has been added as it became available to the marketplace.