The Filter,air Inlet, cataloged under National Stock Number 4520-01-085-1373, is classified within Federal Supply Class 4520 (Space and Water Heating Equipment) of the Plumbing, Heating, and Waste Disposal group. Government technical data includes 2 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4520-01-085-1373 |
| Item Name | Filter,air Inlet |
| FSC / FSG | 4520 / 45 — Space and Water Heating Equipment |
| Status | ACTIVE |
| FSC Application Data | HEATER TRAILER MOUNTED HDU-13M |
| General Characteristics Item Description | COMPOSED OF AIR FILTER 1,FELT STRIP,ADHEISIVE AS REQUIRED,17.750 IN. LG,11.625 IN. W,1.875 IN. H 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 |
|---|---|
| 74094-1 | 5/9 Secondary reference Drs Environmental Systems Inc |
| 74094-1 | 3/2 Design control — primary reference U.S. Government activity |
| 74094-1 | 3/9 Design control — primary reference U.S. Government activity |
NSN 4520-01-085-1373 is a Filter,air Inlet, classified under FSC 4520, Space and Water Heating Equipment. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 1005-01-606-6612. Verify interchangeability with system specifications before substitution.
Key specifications for 4520-01-085-1373: FSC Application Data: HEATER TRAILER MOUNTED HDU-13M; General Characteristics Item Description: COMPOSED OF AIR FILTER 1,FELT STRIP,ADHEISIVE AS REQUIRED,17.750 IN. LG,11.625 IN. W,1.875 IN. H IN. 2 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.