The Valve,restrictor Check, cataloged under National Stock Number 4820-01-052-9688, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Essex Industries, Inc. Dba Essex Industries. Government technical data includes 22 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-052-9688 |
| Primary Part Number | K-1221-8-10 |
| Item Name | Valve,restrictor Check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Essex Industries, Inc. Dba Essex Industries |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Renewable Seat Ring Type | THREADED |
| Connection Style | FLARED (TUBE) FIRST END |
| Mounting Position | HORIZONTAL OR VERTICAL |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Connection Type | THREADED EXTERNAL TUBE SECOND END |
| Style Designator | STRAIGHT THRU |
| Aperture Diameter | 0.016 INCHES NOMINAL IN |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.563 INCHES SECOND END IN |
| Nominal Thread Size | 0.750 INCHES FIRST END IN |
| Seat Angle | 37.0 DEGREES FIRST END |
| Seat Angle | 37.0 DEGREES SECOND END |
| Disk Loading Method | SPRING |
| Thread Class | 3A FIRST END A |
| Thread Class | 3A SECOND END A |
| Material | ALUMINUM BODY |
| Material | IRON CAST FLOW CONTROL DEVICE |
| Thread Series Designator | UNF FIRST END |
| Thread Series Designator | UNF SECOND END |
| 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 |
|---|---|
| K-1221-8-10 PRIMARY | Essex Industries, Inc. Dba Essex Industries (USA) |
| Reference | Meaning |
|---|---|
| 37C301075P105 | 5/2 Secondary reference U.S. Government activity |
NSN 4820-01-052-9688 is a Valve,restrictor Check, manufactured by Essex Industries, Inc. Dba Essex Industries, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-052-9688 has 1 manufacturer part number on file: K-1221-8-10 (Essex Industries, Inc. Dba Essex Industries).
Key specifications for K-1221-8-10: Flow Control Device: DISK; Renewable Seat Ring Type: THREADED; Connection Style: FLARED (TUBE) FIRST END; Mounting Position: HORIZONTAL OR VERTICAL. 22 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.