The Washer,flat, cataloged under National Stock Number 5310-01-381-0552, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Lockheed Martin Corporation Div Rms. 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-01-381-0552 |
| Primary Part Number | 1210B4407 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Lockheed Martin Corporation Div Rms |
| Status | ACTIVE |
| Overall Diameter | 1.755 INCHES NOMINAL IN |
| Surface Treatment | PASSIVATE OVERALL |
| Peripheral Shape Style | ROUND |
| Material | STEEL COMP 316 OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.531 INCHES NOMINAL IN |
| Thickness | 0.250 INCHES NOMINAL IN |
| 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 |
|---|---|
| 1210B4407 PRIMARY | Lockheed Martin Corporation Div Rms (USA) |
| Reference | Meaning |
|---|---|
| 1210B4407 | 5/9 Secondary reference Martin Marietta Technologies Inc Sub of Martin Marietta Corp Aero and Naval Systems |
NSN 5310-01-381-0552 is a Washer,flat, manufactured by Lockheed Martin Corporation Div Rms, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-381-0552 has 1 manufacturer part number on file: 1210B4407 (Lockheed Martin Corporation Div Rms).
1 possible match (shared part number, not a government interchangeability claim): 5310-01-381-9467. Verify interchangeability with system specifications before substitution.
Key specifications for 1210B4407: Overall Diameter: 1.755 INCHES NOMINAL IN; Surface Treatment: PASSIVATE OVERALL; Peripheral Shape Style: ROUND; Material: STEEL COMP 316 OVERALL. 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.