PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

R51ACartridge,respirator,air Filteri

Square D Co Monroe Plant · NSN 4240-01-245-0395 · FSC 4240 · No Item Name Available
Verified by PartsTable
NSN 4240-01-245-0395 — this item is cataloged by the U.S. Government under National Stock Number 4240-01-245-0395. Primary manufacturer part number: R51A.
Features
  • Cartridge,respirator,air Filteri — FSC 4240
  • Hazard Protection Feature: ORGANIC VAPORS
  • Criticality Code Justification: FEAT
  • 6 verified cross-references
  • Primary manufacturer: Square D Co Monroe Plant
Applications
  • Industrial maintenance and repair
  • Government and military logistics
  • Equipment overhaul and refurbishment
General Description

The Cartridge,respirator,air Filteri, cataloged under National Stock Number 4240-01-245-0395, is classified within Federal Supply Class 4240 (No Item Name Available) of the Fire Fighting, Rescue, and Safety Equipment group. The primary manufacturer of record is Square D Co Monroe Plant. Government technical data includes 2 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 6 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4240-01-245-0395
Primary Part NumberR51A
Item NameCartridge,respirator,air Filteri
FSC / FSG4240 / 42 — No Item Name Available
ManufacturerSquare D Co Monroe Plant
StatusACTIVE
Hazard Protection FeatureORGANIC VAPORS
Criticality Code JustificationFEAT
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 12
5133-00-236-4075 INTERCHANGEABLE
Drill,twist
2540-00-359-5835 INTERCHANGEABLE
Cover,fitted,vehicular Body
2940-00-376-85784320512 INTERCHANGEABLE
Filter Element,fluid
Deluxe Products Div Walker Mfg Co
5365-00-576-991051022 INTERCHANGEABLE
Shim
Hydro-Aire Aerospace Corp
5930-00-858-38942E06A11-1 INTERCHANGEABLE
Switch,rotary
Electro Switch Corp. Dba Electro Switch Corp
9905-00-949-50669905009495066 INTERCHANGEABLE
Sign,traffic
Federal Prison Industries, Inc
5310-01-107-770251022 INTERCHANGEABLE
Nut
Mcneil Ohio Corp
5962-01-182-7259338033 INTERCHANGEABLE
Microcircuit,linear
Lockheed Martin Corporation Div Rms - Mitchel Field
2590-01-215-670451022-1 INTERCHANGEABLE
Winch,drum,vehicle Mounting
Tulsa Winch, Inc.
4730-01-253-28495102-2 INTERCHANGEABLE
Strainer Element,sediment
Wisco Products Inc
Cross-Reference Index
Part NumberManufacturer
51022 Aearo Company (USA)
51022 American Optical Co (USA)
51022 Square D Co Monroe Plant (USA)
R51A American Optical Co (USA)
R51A Aearo Company (USA)
R51A PRIMARY Square D Co Monroe Plant (USA)
Related Parts
5133-00-236-4075INTERCHANGEABLE
DRILL,TWIST
2540-00-359-5835INTERCHANGEABLE
COVER,FITTED,VEHICULAR BODY
2940-00-376-8578INTERCHANGEABLE
FILTER ELEMENT,FLUID
4320512
5365-00-576-9910INTERCHANGEABLE
SHIM
51022
5930-00-858-3894INTERCHANGEABLE
SWITCH,ROTARY
2E06A11-1
9905-00-949-5066INTERCHANGEABLE
SIGN,TRAFFIC
9905009495066
5310-01-107-7702INTERCHANGEABLE
NUT
51022
5962-01-182-7259INTERCHANGEABLE
MICROCIRCUIT,LINEAR
338033
2590-01-215-6704INTERCHANGEABLE
WINCH,DRUM,VEHICLE MOUNTING
51022-1
4730-01-253-2849INTERCHANGEABLE
STRAINER ELEMENT,SEDIMENT
5102-2
5962-01-291-5573INTERCHANGEABLE
MICROCIRCUIT,MEMORY
51022-0067
5305-01-322-8675INTERCHANGEABLE
SETSCREW
5102-2

Frequently Asked Questions

What is NSN 4240-01-245-0395?

NSN 4240-01-245-0395 is a Cartridge,respirator,air Filteri, manufactured by Square D Co Monroe Plant, classified under FSC 4240 (No Item Name Available). Status: active.

What are the part numbers for NSN 4240-01-245-0395?

NSN 4240-01-245-0395 has 6 cross-referenced part numbers: 51022 (Aearo Company), 51022 (American Optical Co), 51022 (Square D Co Monroe Plant), R51A (American Optical Co), R51A (Aearo Company) and 1 more.

What NSN replaces 4240-01-245-0395?

There are 12 known substitutes for 4240-01-245-0395: 5133-00-236-4075, 2540-00-359-5835, 2940-00-376-8578 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of R51A?

Key specifications for R51A: Hazard Protection Feature: ORGANIC VAPORS; Special Features: USED ON AMERICAN OPTICAL MODELS R/S4000,R/S5000,R/S6000 AND R/S7000 RESPIRATORS; NIOSH APPROVAL NO. TC-23C-325/326; SOLE SOURCE REQUIRED BY STATUTE 6.302; Criticality Code Justification: FEAT. 3 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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