The Sight Unit, cataloged under National Stock Number 1240-01-691-5144, is classified within Federal Supply Class 1240 (No Item Name Available) of the Fire Control Equipment group. The primary manufacturer of record is Lightforce Usa, Incorporated Div Mil-Gov-Le. Government technical data includes 9 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 1 commercial cross-reference from 1 manufacturer, enabling identification through both NSN and commercial part number lookups. 2 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 1240-01-691-5144 |
| Primary Part Number | M637 |
| Item Name | Sight Unit |
| FSC / FSG | 1240 / 12 — No Item Name Available |
| Manufacturer | Lightforce Usa, Incorporated Div Mil-Gov-Le |
| Status | ACTIVE |
| Scale Markings | PROVIDED |
| Magnification | 2.5 MINIMUM AND 20.0 MAXIMUM |
| Straight Type Overall Length | 305.0 MILLIMETERS NOMINAL MM |
| Diopter Scale | INCLUDED |
| Focusing Type | ADJUSTABLE |
| Optical Device Type | LENS |
| Objective Aperture Diameter | 59.0 MILLIMETERS NOMINAL MM |
| Magnification Type | VARIABLE |
| Field View Coverage | 2.5X:41.8 FT. 20X: 7.0 FT. FT |
| Acquisition Status | ACTIVE |
| HAZMAT | No |
| Part Number | Manufacturer |
|---|---|
| M637 PRIMARY | Lightforce Usa, Incorporated Div Mil-Gov-Le (USA) |
NSN 1240-01-691-5144 is a Sight Unit, manufactured by Lightforce Usa, Incorporated Div Mil-Gov-Le, classified under FSC 1240 (No Item Name Available). Status: active.
NSN 1240-01-691-5144 has 1 cross-referenced part number: M637 (Lightforce Usa, Incorporated Div Mil-Gov-Le).
There are 2 known substitutes for 1240-01-691-5144: 6625-01-005-6584, 5840-01-135-6410. Verify interchangeability with system specifications before substitution.
Key specifications for M637: Scale Markings: PROVIDED; Magnification: 2.5 MINIMUM AND 20.0 MAXIMUM; Straight Type Overall Length: 305.0 MILLIMETERS NOMINAL MM; Diopter Scale: INCLUDED. 10 total characteristics are documented in the Federal Logistics Information System.