The Cartridge,respirator,air Filteri, cataloged under National Stock Number 4240-01-245-3329, 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 Square D Co Monroe Plant. Government technical data includes 2 specifications, cited from the U.S. Government catalog. The record lists 4 manufacturer part numbers 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 4240-01-245-3329 |
| Primary Part Number | R55A |
| Item Name | Cartridge,respirator,air Filteri |
| FSC / FSG | 4240 / 42 — Safety and Rescue Equipment |
| Manufacturer | Square D Co Monroe Plant |
| Status | ACTIVE |
| Hazard Protection Feature | ORGANIC VAPORS |
| 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 |
|---|---|
| R55A PRIMARY | Square D Co Monroe Plant (USA) |
| 51038 | Square D Co Monroe Plant (USA) |
| R55A | American Optical Co (USA) |
| 51038 | American Optical Co (USA) |
| Reference | Meaning |
|---|---|
| R55A | 3/9 Design control — primary reference U.S. Government activity |
| 51038 | 5/9 Secondary reference U.S. Government activity |
NSN 4240-01-245-3329 is a Cartridge,respirator,air Filteri, manufactured by Square D Co Monroe Plant, classified under FSC 4240, Safety and Rescue Equipment. Status: active.
NSN 4240-01-245-3329 has 4 manufacturer part numbers on file: R55A (Square D Co Monroe Plant), 51038 (Square D Co Monroe Plant), R55A (American Optical Co), 51038 (American Optical Co).
Key specifications for R55A: Hazard Protection Feature: ORGANIC VAPORS; Criticality Code Justification: FEAT; Special Features: USED ON AMERICAN OPTICAL MODELS R/S4000,R/S5000,R/S6000 AND R/S7000 RESPIRATORS; NIOSH APPROVED TC-23C-488/489; SOLE SOURCE REQUIRED BY STATUTE 6.302. 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.