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		                        | National Stock Number:
 1240-01-170-0860
 
 Federal Supply Class:
 1240
 
 National Item Identification Number:
 011700860
 
 Description:
 WINDOW,OPTICAL INSTRUMENT
 
 Detail:
 A COLOR FREE ITEM OF TRANSPARENT OR TRANSLUCENT MATERIAL, USUALLY OPTICAL GLASS, HAVING SPECIFIC LIGHT DISPERSIVE AND REFRACTIVE PROPERTIES. THIS ITEM MUST HAVE TWO PLANE-PARALLEL SURFACES AND IS DESIGNED FOR USE IN AN OPTICAL INSTRUMENT TO PROVIDE A BARRIER TO FOREIGN MATTER AND/OR PERMIT LIGHT TRANSMISSION IN OR TO THE OPTICAL SYSTEM.
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 Manufacturer Information:
 
 | 13074463 | 04939 | LOCKHEED MARTIN CORPORATION |  | 13074463 | 58260 | PROGRAM MANAGER ADVANCED ATTACK HELICOPTER BARCOM AMCPM-AAH | 
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 Techincal Specification:
 
 | MATERIAL DOCUMENT AND CLASSIFICATION | MIL-G-174, CLASS 1, GRADE C, TYPE 617-549 MIL SPEC SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED |  | MATERIAL | GLASS OPTICAL LOCATION NOT OTHERWISE SPECIFIED |  | POLISHED PERIPHERY | PROVIDED | 
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