Eldon - MIL-P-13949 and its successor, MIL-S-13949 were both laminate specifications for a wide variety of epoxy, polyimide, aramid and other materials. They covered clad, unclad and B-staged materials. These materials included FR-4 and many other grades of laminate. MIL-S-13949 was cancelled in November 1998. This means the laminate suppliers, for the most part are no longer supplying materials certified to that document. If you don't require certification, the laminates can still be procured, or they can be procured under another specification, such as IPC-4101 Recommend you solicit your customers approval to convert to an equivalent grade of laminate material under IPC-4101. This document contains a handy conversion list on page 19, or most laminate suppliers are willing to assist in the process. Regards - Kelly ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################