The Filter,respirator,air Filtering, cataloged under National Stock Number 4240-01-251-5340, is classified within Federal Supply Class 4240 (Safety and Rescue Equipment) of the Fire Fighting, Rescue, and Safety Equipment group. The manufacturer of record is American Optical Co. Government technical data includes 2 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4240-01-251-5340 |
| Primary Part Number | R90N-5EA |
| Item Name | Filter,respirator,air Filtering |
| FSC / FSG | 4240 / 42 — Safety and Rescue Equipment |
| Manufacturer | American Optical Co |
| Status | ACTIVE |
| FSC Application Data | RESPIRATOR,AIR FILTERING |
| Criticality Code Justification | FEAT |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | Possible hazard — SDS may be required (DLA HMIC P) |
| Criticality Code | Y |
| Part Number | Manufacturer |
|---|---|
| R90N-5EA | American Optical Co (USA) |
| Reference | Meaning |
|---|---|
| R90N-5EA | C/1 Advisory reference — outside the item-of-supply concept Square D Co Monroe Plant |
| R90N-5EA | 3/9 Design control — primary reference U.S. Government activity |
NSN 4240-01-251-5340 is a Filter,respirator,air Filtering, manufactured by American Optical Co, classified under FSC 4240, Safety and Rescue Equipment. Status: active.
NSN 4240-01-251-5340 has 1 manufacturer part number on file: R90N-5EA (American Optical Co).
Key specifications for R90N-5EA: FSC Application Data: RESPIRATOR,AIR FILTERING; Criticality Code Justification: FEAT; Special Features: SOLE SOURCE REQUIRED BY STATUTE 6.302; USED ON AMERICAN OPTICAL MODEL R2090N RESPIRATOR. 2 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.