The Collar,air Conditioning-Heating, cataloged under National Stock Number 4520-01-161-6581, is classified within Federal Supply Class 4520 (Space and Water Heating Equipment) of the Plumbing, Heating, and Waste Disposal group. Government technical data includes 6 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government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 | 4520-01-161-6581 |
| Item Name | Collar,air Conditioning-Heating |
| FSC / FSG | 4520 / 45 — Space and Water Heating Equipment |
| Status | ACTIVE |
| Fitting Inside Diameter | 18.000 INCHES NOMINAL IN |
| Style Designator | ROUND |
| Sheet Metal Gage Size | 20 |
| Surface Treatment | ZINC |
| Material | STEEL |
| Fitting Overall Length | 4.000 INCHES NOMINAL IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| 14-2-18 | 3/9 Design control — primary reference United Mcgill Corp |
NSN 4520-01-161-6581 is a Collar,air Conditioning-Heating, classified under FSC 4520, Space and Water Heating Equipment. Status: active.
3 possible matches (shared part number, not a government interchangeability claim): 6150-01-265-2656, 5325-01-283-3513, 3020-01-322-1795. Verify interchangeability with system specifications before substitution.
Key specifications for 4520-01-161-6581: Fitting Inside Diameter: 18.000 INCHES NOMINAL IN; Style Designator: ROUND; Sheet Metal Gage Size: 20; Surface Treatment: ZINC. 6 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.