The Washer,lock, cataloged under National Stock Number 5310-00-641-9379, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is United Technologies Corp Electro Systems Inc. Government technical data includes 5 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-641-9379 |
| Primary Part Number | WA21-4 |
| Item Name | Washer,lock |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | United Technologies Corp Electro Systems Inc |
| Status | ACTIVE |
| Style Designator | FLAT EXTERNAL TEETH |
| Outside Diameter | 0.370 INCHES MINIMUM AND 0.381 INCHES MAXIMUM IN |
| Material Thickness | 0.020 INCHES NOMINAL IN |
| Material | STEEL OVERALL |
| Hole Diameter | 0.168 INCHES MINIMUM AND 0.176 INCHES MAXIMUM 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 |
|---|---|
| WA21-4 PRIMARY | United Technologies Corp Electro Systems Inc (USA) |
| Reference | Meaning |
|---|---|
| WA21-4 | 5/9 Secondary reference Ambac International Corporation Div Ambac International |
NSN 5310-00-641-9379 is a Washer,lock, manufactured by United Technologies Corp Electro Systems Inc, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-641-9379 has 1 manufacturer part number on file: WA21-4 (United Technologies Corp Electro Systems Inc).
Key specifications for WA21-4: Style Designator: FLAT EXTERNAL TEETH; Outside Diameter: 0.370 INCHES MINIMUM AND 0.381 INCHES MAXIMUM IN; Material Thickness: 0.020 INCHES NOMINAL IN; Material: STEEL OVERALL. 5 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.