The Clamp,loop, cataloged under National Stock Number 5340-01-471-0251, is classified within Federal Supply Class 5340 (Hardware, Commercial) of the Hardware and Abrasives group. The manufacturer of record is The Boeing Company. Government technical data includes 13 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active. Unit of issue: EA.
| Parameter | Value |
|---|---|
| NSN | 5340-01-471-0251 |
| Primary Part Number | HS4181A64N |
| Item Name | Clamp,loop |
| FSC / FSG | 5340 / 53 — Hardware, Commercial |
| Manufacturer | The Boeing Company |
| Status | ACTIVE |
| Cushioning Environmental Protection | OZONE RESISTANT |
| Material Diameter | 4.000 INCHES NOMINAL IN |
| Style Designator | SADDLE MOUNT |
| Material Document and Classification | QQ-A-250/5 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Material Document and Classification | AMS 3209 FED STD SINGLE MATERIAL RESPONSE CUSHION |
| Diameter | 4.000 INCHES NOMINAL IN |
| Material Thickness | 0.051 INCHES NOMINAL IN |
| Distance From Loop Center to Tongue End | 2.780 INCHES NOMINAL IN |
| Tongue Hole Type | ROUND, UNTHREADED |
| Center to Center Distance Between Loop and Mounting Hole | 2.530 INCHES NOMINAL IN |
| Material | ALUMINUM ALLOY OVERALL |
| Material | RUBBER CHLOROPRENE CLASS CR CUSHION |
| Loop Inside Diameter | 4.000 INCHES NOMINAL IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | Possible hazard — SDS may be required (DLA HMIC P) |
| Criticality Code | X |
| Unit of Issue | EA |
| Part Number | Manufacturer |
|---|---|
| HS4181A64N PRIMARY | The Boeing Company (USA) |
| Reference | Meaning |
|---|---|
| 11281-64N | 5/2 Secondary reference U.S. Government activity |
| 11281-64N | 5/9 Secondary reference Transdigm Inc Div Adelwiggins Group |
| 11281-A64N | 5/9 Secondary reference Transdigm Inc Div Adelwiggins Group |
| HS4181A64N | 5/9 Secondary reference Mcdonnell Douglas Helicopter Co Inc |
NSN 5340-01-471-0251 is a Clamp,loop, manufactured by The Boeing Company, classified under FSC 5340, Hardware, Commercial. Status: active.
NSN 5340-01-471-0251 has 1 manufacturer part number on file: HS4181A64N (The Boeing Company).
Key specifications for HS4181A64N: Cushioning Environmental Protection: OZONE RESISTANT; Material Diameter: 4.000 INCHES NOMINAL IN; Style Designator: SADDLE MOUNT; Material Document and Classification: QQ-A-250/5 FED SPEC SINGLE MATERIAL RESPONSE OVERALL. 13 specifications are documented in the U.S. Government catalog.
Possible hazard — SDS may be required (DLA HMIC P). 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.