The Seat,valve, cataloged under National Stock Number 4820-01-125-9773, 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6 specifications, cited from the U.S. Government catalog. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-125-9773 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flange Diameter | 20.700 INCHES NOMINAL IN |
| Body Outside Diameter | 16.000 INCHES NOMINAL IN |
| Body Inside Diameter | 13.000 INCHES NOMINAL IN |
| Under Flange Height | 3.250 INCHES NOMINAL IN |
| Material | COPPER ALLOY OVERALL |
| Seating Surface Shape | FLAT |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| 501-4675697 ITEM 3 | 5/2 Secondary reference U.S. Government activity |
| 87643-7503 ITEM 3 | 3/2 Design control — primary reference U.S. Government activity |
| 87643-7503 | D/9 Drawing number reference only U.S. Government activity |
| 501-4675697 | D/9 Drawing number reference only U.S. Government activity |
NSN 4820-01-125-9773 is a Seat,valve, classified under FSC 4820, Valves, Nonpowered. Status: active.
2 possible matches (shared part number, not a government interchangeability claim): 4820-01-153-1625, 4820-01-192-3590. Verify interchangeability with system specifications before substitution.
Key specifications for 4820-01-125-9773: Flange Diameter: 20.700 INCHES NOMINAL IN; Body Outside Diameter: 16.000 INCHES NOMINAL IN; Body Inside Diameter: 13.000 INCHES NOMINAL IN; Under Flange Height: 3.250 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.
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.