I have a customer spec'ing the following FL-GF020C1/1BIIA OK, so I know(?) that this is a MIL-S-13949 spec. I don't have an old copy so have done the requisite "Google" and Technet Archive search in an attempt to understand this so I can cross it to IPC-4101. I could use some help. 1. FL = Flexible laminate correct? TL = thin laminate?? What is the difference in construction for a given dielectric thickness (020)? 2. "B" after C1/1 still refers to thickness tolerance? Does it equate to "B" in 4101? 3. What is "IIA" after the "B"? 4. Anyone want to provide the exact 4101 equivalent callout for the above spec? Happy Friday! John Parsons --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------