Randy, IPC-L-108B and IPC-L-109B are the specifications that address laminate and prepreg respectfully. However, I believe that they allowed 1 ply constructions prior to the military specification change. I can't verify that since I don't have those standards at hand. As for concerns about 1 ply constructions, not all one ply alternatives can match the thickness of the two ply core that it's replacing, and there will be a slight difference in electrical performance. However, thickness variability will be better, and of course the cost advantage of the one ply. You really shouldn't see any problems with voiding or measling unless the supplier has adjusted their process parameters to try to get a greater thickness. Hope this helps. Glenn Pelkey Maxtek Components Corp. (503) 627-2084 *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************