The Retainer,seat,valve, cataloged under National Stock Number 4820-01-428-8798, 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 3 specifications, cited from the U.S. Government catalog. The record lists 3 manufacturer part numbers 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 7 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-428-8798 |
| Primary Part Number | 218012887 |
| Item Name | Retainer,seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Sea Systems Command |
| Status | ACTIVE |
| Material Document and Classification | ASTM B15 ALLOY C632000 ASSN STD SINGLE MATERIAL RESPONSE |
| Valve Design Control Activity | 53711 |
| Material | COPPER ALLOY |
| 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 |
|---|---|
| 6406593-MPTD-A8, -B8 | Naval Sea Systems Command (USA) |
| 556-6406593-MTPD-A8 | Naval Sea Systems Command (USA) |
| 218012887 PRIMARY | Naval Sea Systems Command (USA) |
| Reference | Meaning |
|---|---|
| 6406593 | D/9 Drawing number reference only Naval Sea Systems Command |
| C791-6301 FN MTPD-A8 | 5/9 Secondary reference U.S. Government activity |
| 6406593-MTPD-A8 | C/1 Advisory reference — outside the item-of-supply concept Naval Sea Systems Command |
NSN 4820-01-428-8798 is a Retainer,seat,valve, manufactured by Naval Sea Systems Command, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-428-8798 has 3 manufacturer part numbers on file: 6406593-MPTD-A8, -B8 (Naval Sea Systems Command), 556-6406593-MTPD-A8 (Naval Sea Systems Command), 218012887 (Naval Sea Systems Command).
7 possible matches (shared part number, not a government interchangeability claim): 4820-01-429-0161, 4820-01-429-0165, 4820-01-429-0168. Verify interchangeability with system specifications before substitution.
Key specifications for 218012887: Material Document and Classification: ASTM B15 ALLOY C632000 ASSN STD SINGLE MATERIAL RESPONSE; Special Features: CONSISTS OF 6406593-MPTD-A8 AND 6406593-MPTD-B8,INSIDE DIAMETER IS 1.250 IN. NOMINAL IN; Valve Design Control Activity: 53711; End Item Identification: SEAWOLF CLASS SSN. 3 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.