This standard establishes the classification system@ the qualification and quality conformance requirements for flexible base dielectric materials to be used for the fabrication of flexible printed boards. This specification supersedes IPC-4202 which@ in turn superseded IPC-FC-231C and the requirements herein meet or exceed the requirements for Class 3 in this superseded document. Note that conformance to Class 3 met or exceeded conformance to Classes 1 and 2. IPC-4202 no longer utilizes the 3-class system.