The Seat,valve, cataloged under National Stock Number 4820-01-121-1439, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Naval Sea Systems Command. Government technical data includes 8 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-121-1439 |
| Primary Part Number | 518-4674803 ITEM 7 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Sea Systems Command |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.090 INCHES NOMINAL IN |
| Flange Diameter | 1.000 INCHES NOMINAL IN |
| Body Outside Diameter | 0.750 INCHES NOMINAL IN |
| Style Designator | PLAIN FLANGED |
| Body Inside Diameter | 0.375 INCHES NOMINAL IN |
| Under Flange Height | 1.260 INCHES NOMINAL IN |
| Material | COPPER ALLOY OVERALL |
| Seating Surface Shape | O-RING |
| 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 |
|---|---|
| 518-4674803 ITEM 7 | Naval Sea Systems Command (USA) |
| Reference | Meaning |
|---|---|
| 518-4674803 ITE | C/1 Advisory reference — outside the item-of-supply concept U.S. Government activity |
| 87625-0305 ITEM 7 | 3/2 Design control — primary reference U.S. Government activity |
| 518-4674803 | D/9 Drawing number reference only Naval Sea Systems Command |
NSN 4820-01-121-1439 is a Seat,valve, manufactured by Naval Sea Systems Command, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-121-1439 has 1 manufacturer part number on file: 518-4674803 ITEM 7 (Naval Sea Systems Command).
Key specifications for 518-4674803 ITEM 7: Flange Seat to Disk End Height: 0.090 INCHES NOMINAL IN; Flange Diameter: 1.000 INCHES NOMINAL IN; Body Outside Diameter: 0.750 INCHES NOMINAL IN; Style Designator: PLAIN FLANGED. 8 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.