The Ring,retaining,optical Element, cataloged under National Stock Number 1240-00-159-0537, is classified within Federal Supply Class 1240 (Optical Sighting and Ranging Equipment) of the Fire Control Equipment group. The manufacturer of record is Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier. Government technical data includes 7 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 1240-00-159-0537 |
| Primary Part Number | 655045 |
| Item Name | Ring,retaining,optical Element |
| FSC / FSG | 1240 / 12 — Optical Sighting and Ranging Equipment |
| Manufacturer | Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier |
| Status | ACTIVE |
| Groove Location | INSIDE FACE OF FLANGE |
| Internal Flange Thickness | 0.125 INCHES NOMINAL IN |
| Groove Diameter | 2.251 INCHES NOMINAL IN |
| Outside Diameter | 2.500 INCHES NOMINAL IN |
| Aperture Diameter | 2.016 INCHES NOMINAL IN |
| Inner Groove Width | 0.0235 INCHES NOMINAL IN |
| Material | STEEL CORROSION RESISTING |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 655045 PRIMARY | Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier (USA) |
| Reference | Meaning |
|---|---|
| 231650 | 5/9 Secondary reference Lockheed Martin Corporation Div Rms - Mitchel Field |
NSN 1240-00-159-0537 is a Ring,retaining,optical Element, manufactured by Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier, classified under FSC 1240, Optical Sighting and Ranging Equipment. Status: active.
NSN 1240-00-159-0537 has 1 manufacturer part number on file: 655045 (Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier).
3 possible matches (shared part number, not a government interchangeability claim): 5961-00-521-2502, 6550-01-300-8697, 7045-01-580-5876. Verify interchangeability with system specifications before substitution.
Key specifications for 655045: Groove Location: INSIDE FACE OF FLANGE; Internal Flange Thickness: 0.125 INCHES NOMINAL IN; Groove Diameter: 2.251 INCHES NOMINAL IN; Overall Length: 0.656 INCHES NOMINAL IN. 7 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.
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.