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		                        | National Stock Number:
 1240-00-609-5420
 
 Federal Supply Class:
 1240
 
 National Item Identification Number:
 006095420
 
 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:
 
 | 322968PC11 | 10001 | NAVAIR AND NAVSEA MANAGED ORIGINAL DESIGN ACTIVITY DWG NOT MATERIAL/PARTS SUPPLIER |  | G11594PC11 | 74067 | KEUFFEL AND ESSER CO | 
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 Techincal Specification:
 
 | DIAMETER | 34.0 MILLIMETERS NOMINAL |  | MATERIAL DOCUMENT AND CLASSIFICATION | JAN-G-174, GRADE A MIL SPEC SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED |  | MATERIAL | GLASS OPTICAL LOCATION NOT OTHERWISE SPECIFIED |  | POLISHED PERIPHERY | NOT PROVIDED |  | REFRACTION INDEX | 1.5170 NOMINAL |  | THICKNESS | 6.0 MILLIMETERS NOMINAL | 
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