The phrase “see-through rule” is a colloquial phrase popularly used to refer to the impact of certain ITAR controls.  Specifically, it refers to the fact that pursuant to ITAR §120.6, any item described on the USML is a defense article.  ITAR § 123.1(a) further provides that any person who intends to export or temporarily import a defense article must obtain the approval of DDTC prior to the export or temporary import, and ITAR § 123.9(a) requires the written approval of DDTC before reselling, transferring, reexporting, retransferring, transshipping, or disposing of a defense article to any end-user, end-use, or destination other than as stated on the export license, except in accordance with the provisions of an applicable exemption.  These controls do not disappear simply because the defense article is integrated into another item.  If an ITAR-controlled defense article is integrated into a larger system or end-item, the defense article does not lose its identity.  Except as articulated specifically in the USML (see e.g., USML Category XV, Note 2 to paragraph (e)) the ITAR “sees through” the larger system or end-item and continues to regulate that defense article.