The Valve,check, cataloged under National Stock Number 4820-01-125-9747, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Emerson Automation Solutions Final Control Us Lp Div Navy Product Team. Government technical data includes 19 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 7 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-125-9747 |
| Primary Part Number | NS3981ASSYB |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Flange Shape | ROUND WITH HOLES ALL ENDS |
| Flange Face Design | PLAIN ALL ENDS |
| Bolt Circle Nominal Diameter | 5.938 INCHES ALL ENDS IN |
| Mounting Position | HORIZONTAL |
| Connection Type | FLANGE ALL ENDS |
| Style Designator | STRAIGHT THRU FLANGED ENDS |
| Material Document and Classification | QQ-C-390,ALLOY D5/D FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Bolt Hole Nominal Diameter | 0.687 INCHES ALL ENDS IN |
| Operating Pressure | 1050.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Valve Size | 3.000 INCHES IN |
| Maximum Operating Temp | 150.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Nominal Outside Diameter | 7.438 INCHES ALL ENDS IN |
| Bolt Hole Quantity | 8 ALL ENDS |
| Face to Face Distance | 11.750 INCHES IN |
| Media for Which Designed | WATER-OIL-GAS SINGLE RESPONSE |
| Material | COPPER ALLOY 903 OVERALL |
| Valve Operation Method | AUTOMATIC |
| Nominal Thickness | 1.062 INCHES ALL ENDS 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 |
|---|---|
| NS3981ASSYB PRIMARY | Emerson Automation Solutions Final Control Us Lp Div Navy Product Team (USA) |
| Reference | Meaning |
|---|---|
| NS-3981 | D/9 Drawing number reference only Emerson Automation Solutions Final Control Us Lp Div Navy Product Team |
| NS3981ASSYB | 5/9 Secondary reference National Oilwell |
| NS-3981 | 5/9 Secondary reference National Oilwell |
NSN 4820-01-125-9747 is a Valve,check, manufactured by Emerson Automation Solutions Final Control Us Lp Div Navy Product Team, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-125-9747 has 1 manufacturer part number on file: NS3981ASSYB (Emerson Automation Solutions Final Control Us Lp Div Navy Product Team).
7 possible matches (shared part number, not a government interchangeability claim): 4820-01-125-9993, 4820-01-145-6249, 4820-01-146-7060. Verify interchangeability with system specifications before substitution.
Key specifications for NS3981ASSYB: Flow Control Device: DISK; Flange Shape: ROUND WITH HOLES ALL ENDS; Flange Face Design: PLAIN ALL ENDS; Bolt Circle Nominal Diameter: 5.938 INCHES ALL ENDS IN. 19 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.