What is
the MOS?

GLOCK engineers have developed the glock modular optic system to simplify mounting of popular optic sights without costly custom machining of the pistol’s slide. Optical sights are popular in competitive shooting and are becoming increasingly popular for concealed carry, home defense and target shooters.

What calibers are
being offered?

GLOCK now offers six of the most popular pistols configured in MOS (Modular Optic System). The models that may be ordered in the mos configuration are the G17 Gen4, G19 Gen4, G34 Gen4, G35 Gen4, G41 Gen4, and G40 Gen4 MOS. Specifications of these models do not vary from their respective gen4 configurations.

*Optic Not Included
Available Models
G34 | G35 | G41 | G40


Quicker sight acquisition of your target.


Faster target transition.


The modular optic system gives you
the option of adding tall iron sights
that allow the optic and iron sights
to co-witness providing backup in the
case of optic failure.



Improved accuracy at
both long and short range.

*Optic not included

What is the process
to add an optic?

The GLOCK MOS allows the shooter to mount the sight of their choice,
easily and quickly using only a few tools. The versatility of the system
makes changing optics easy. Switching from one sight to another is as
simple as removing the old sight, removing and reinstalling the
correct adapter plate, then mounting the new sight.

The MOS is offered with a cover plate when no optic is mounted and four different plate options to comply with the specifications of some of the most trusted optic manufacturers in the industry.


Cover Plate
Eotech / Docter / Insight / Meopta
Trijicon RMR
Leupold Delta Point

*The G40 Gen4 MOS comes with Adapter-Set 02, and has slightly wider plates to accommodate the width of the G40 Gen4 MOS slide.

*Optic not included

What's the difference
between reflex optics
(MOS) and standard
iron sights?

With the reflex optics, you look through the reticle and focus on the target and alignment of the dot.

With standard iron sight shooting, you align the front and rear sight with a hard focus on the front sight.

*Optic not included

What is the
of dot size?

Large dots are easily picked up in bright light and at close range. While a smaller dot is better for low light and longer distance target.

Adjust the sliders to see
how dot size relates
to target distance
  • 3 MOA
  • 7 MOA
Dot Size

Reflex sights commonly come with either large dots, which are approximately 7 minutes of angle (MOA) or approximately 3 MOA. 3 MOA covers 3 inches at 100 yards and 7 MOA covers 7 inches at 100 yards. Coverage of each dot size would be 1/2 at 50 yards.

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