The Window,optical Instrument, cataloged under National Stock Number 1240-01-068-0399, is classified within Federal Supply Class 1240 (Optical Sighting and Ranging Equipment) of the Fire Control Equipment group. Government technical data includes 6 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 1240-01-068-0399 |
| Item Name | Window,optical Instrument |
| FSC / FSG | 1240 / 12 — Optical Sighting and Ranging Equipment |
| Status | ACTIVE |
| Length | 3.370 INCHES NOMINAL IN |
| Material Document and Classification | MIL-G-174, CLASS 1, GRADE A, TYPE 517-642 MIL SPEC SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED |
| Polished Periphery | PROVIDED |
| Width | 1.670 INCHES NOMINAL IN |
| Material | GLASS OPTICAL LOCATION NOT OTHERWISE SPECIFIED |
| Thickness | 0.200 INCHES NOMINAL IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL D — Destroy Item |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| SM-D-805048 | 3/2 Design control — primary reference U.S. Government activity |
NSN 1240-01-068-0399 is a Window,optical Instrument, classified under FSC 1240, Optical Sighting and Ranging Equipment. Status: active.
Key specifications for 1240-01-068-0399: Length: 3.370 INCHES NOMINAL IN; Material Document and Classification: MIL-G-174, CLASS 1, GRADE A, TYPE 517-642 MIL SPEC SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED; Polished Periphery: PROVIDED; Special Features: MATERIAL USED IN THE MANUFACTURE OF THIS OPTICAL PART SHALL NOT CONTAINTHORIUM,OTHER RADIOACTVE MATERIAL,OR ANY COMBINATION OF NUCLEAR MATERIALS INEXCESS OF 0.05 PERCENT BY WEIGHT AS DEFINED BY THE TITLE 10,CODE OF FEDERAL REGULATIONS,PART 40. 6 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
NSN 1240-01-068-0399 has DEMIL Code D. Demilitarization may be required before disposal or transfer to non-military entities.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.