The Piston,valve, cataloged under National Stock Number 4820-01-439-3971, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves 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6 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 4820-01-439-3971 |
| Item Name | Piston,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Outside Diameter | 1.238 INCHES MINIMUM AND 1.239 INCHES MAXIMUM IN |
| Features Provided | THREADED |
| Inside Diameter | 0.375 INCHES NOMINAL IN |
| Surface Treatment | PASSIVATE |
| Valve Design Control Activity | 99240 |
| Material | STEEL |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL B — Remove Demilitarization Key Points |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| 2A1021-4 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-01-439-3971 is a Piston,valve, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-439-3971: Outside Diameter: 1.238 INCHES MINIMUM AND 1.239 INCHES MAXIMUM IN; Overall Length: 3.465 INCHES NOMINAL IN; Features Provided: THREADED; Inside Diameter: 0.375 INCHES NOMINAL IN. 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 4820-01-439-3971 has DEMIL Code B. 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.