The Hose,air Duct, cataloged under National Stock Number 4720-01-042-0256, is classified within Federal Supply Class 4720 (Hose and Flexible Tubing) of the Pipe, Tubing, Hose, and Fittings group. The manufacturer of record is Hbd Industries, Inc Div Hbd/thermoid Inc. Government technical data includes 12 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4720-01-042-0256 |
| Primary Part Number | AD-604-3 |
| Item Name | Hose,air Duct |
| FSC / FSG | 4720 / 47 — Hose and Flexible Tubing |
| Manufacturer | Hbd Industries, Inc Div Hbd/thermoid Inc |
| Status | ACTIVE |
| Measuring Method and Length | 22.000 INCHES NOMINAL OVERALL IN |
| Connection Style | ROUND BOTH ENDS |
| Connection Type | PREFORMED BOTH ENDS |
| Style Designator | FULLY CONVOLUTED |
| Cross-Sectional Shape Style | ROUND |
| Wall Thickness | 0.200 INCHES NOMINAL IN |
| Inside Diameter | 0.750 INCHES NOMINAL FIRST END IN |
| End Overall Length | 0.620 INCHES NOMINAL BOTH ENDS IN |
| End Inside Diameter | 0.750 INCHES NOMINAL BOTH ENDS IN |
| Material | FIBERGLASS SECOND PLY |
| Material | RUBBER SILICONE CLASS Q COVER |
| Material | FIBERGLASS FIRST PLY |
| 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 |
|---|---|
| AD-604-3 PRIMARY | Hbd Industries, Inc Div Hbd/thermoid Inc (USA) |
| Reference | Meaning |
|---|---|
| AD604-3 | 3/2 Design control — primary reference U.S. Government activity |
| AD-604 | D/9 Drawing number reference only Hbd Industries, Inc Div Hbd/thermoid Inc |
NSN 4720-01-042-0256 is a Hose,air Duct, manufactured by Hbd Industries, Inc Div Hbd/thermoid Inc, classified under FSC 4720, Hose and Flexible Tubing. Status: active.
NSN 4720-01-042-0256 has 1 manufacturer part number on file: AD-604-3 (Hbd Industries, Inc Div Hbd/thermoid Inc).
Key specifications for AD-604-3: Measuring Method and Length: 22.000 INCHES NOMINAL OVERALL IN; Connection Style: ROUND BOTH ENDS; Connection Type: PREFORMED BOTH ENDS; Style Designator: FULLY CONVOLUTED. 12 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.