The Valve,check, cataloged under National Stock Number 4820-01-121-0844, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Raytheon Company Div Rmd Strategic. Government technical data includes 16 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 4 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-121-0844 |
| Primary Part Number | 721904-6 |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Raytheon Company Div Rmd Strategic |
| Status | ACTIVE |
| Connection Style | PLAIN, OPTIONAL END (PIPE) ALL ENDS |
| Mounting Position | HORIZONTAL OR VERTICAL |
| Supplementary Features | FLOW CONTROL DEVICE: DIAPHRAGM |
| Connection Type | THREADED INTERNAL PIPE ALL ENDS |
| Style Designator | STRAIGHT THRU |
| Material Document and Classification | QQ-B-626 FED SPEC SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | MIL-P-5315 MIL SPEC SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Operating Pressure | 160.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.500 INCHES ALL ENDS IN |
| Maximum Operating Temp | 160.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Media for Which Designed | WATER, FRESH SINGLE RESPONSE |
| Material | COPPER ALLOY BODY |
| Material | RUBBER BUTADIENE-ACRYLONITRILE CLASS NBR FLOW CONTROL DEVICE |
| Thread Series Designator | NPT ALL ENDS |
| Valve Operation Method | AUTOMATIC |
| 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 |
|---|---|
| 721904-6 | Raytheon Company Div Rmd Strategic (USA) |
| Reference | Meaning |
|---|---|
| 1-2-2305-1081 | 3/2 Design control — primary reference U.S. Government activity |
| 721904 | D/9 Drawing number reference only Raytheon Company Div Rmd Strategic |
NSN 4820-01-121-0844 is a Valve,check, manufactured by Raytheon Company Div Rmd Strategic, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-121-0844 has 1 manufacturer part number on file: 721904-6 (Raytheon Company Div Rmd Strategic).
4 possible matches (shared part number, not a government interchangeability claim): 4820-01-187-2270, 4820-01-322-2128, 4820-01-322-6644. Verify interchangeability with system specifications before substitution.
Key specifications for 721904-6: Connection Style: PLAIN, OPTIONAL END (PIPE) ALL ENDS; Mounting Position: HORIZONTAL OR VERTICAL; Supplementary Features: FLOW CONTROL DEVICE: DIAPHRAGM; Connection Type: THREADED INTERNAL PIPE ALL ENDS. 16 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.