The Indicator Filter, cataloged under National Stock Number 6680-01-457-9002, is classified within Federal Supply Class 6680 (Liquid and Gas Flow, Liquid Level, and Mechanical Motion Measuring Instruments) of the Instruments and Laboratory Equipment group. The manufacturer of record is Air Systems International, Inc. (used in VA by: Air Systems, Inc.) Dba Air Systems International Inc. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government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 | 6680-01-457-9002 |
| Primary Part Number | WL056 |
| Item Name | Indicator Filter |
| FSC / FSG | 6680 / 66 — Liquid and Gas Flow, Liquid Level, and Mechanical Motion Measuring Instruments |
| Manufacturer | Air Systems International, Inc. (used in VA by: Air Systems, Inc.) Dba Air Systems International Inc |
| Status | ACTIVE |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| WL056 PRIMARY | Air Systems International, Inc. (used in VA by: Air Systems, Inc.) Dba Air Systems International Inc (USA) |
| Reference | Meaning |
|---|---|
| BB100NNS26 | D/9 Drawing number reference only Air Systems International, Inc. (used in VA by: Air Systems, Inc.) Dba Air Systems International Inc |
NSN 6680-01-457-9002 is a Indicator Filter, manufactured by Air Systems International, Inc. (used in VA by: Air Systems, Inc.) Dba Air Systems International Inc, classified under FSC 6680, Liquid and Gas Flow, Liquid Level, and Mechanical Motion Measuring Instruments. Status: active.
NSN 6680-01-457-9002 has 1 manufacturer part number on file: WL056 (Air Systems International, Inc. (used in VA by: Air Systems, Inc.) Dba Air Systems International Inc).
3 possible matches (shared part number, not a government interchangeability claim): 4820-01-458-0400, 4940-01-463-8561, 4330-01-464-2056. Verify interchangeability with system specifications before substitution.
Key specifications for WL056: Special Features: DIFFERENTIAL PRESSURE INDICATOR TO CHANGE FILTER,WHEN PRESSURE RISES, INDICATOR WILL LET YOU KNOW TO CHANGE FILTER. 0 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.