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// 29.9.2023 GA4 add to cart // 29.9.2023 GA4 add to cart

Holosun 403B

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Holosun 403B Details

About the Holosun 403B red dot

Holosun 403B is a red dot sight of the Holosun Paralow series. 

This sight is a great choice not only for standard hunting rifles and AR-rifles but also shotguns, pistols, air rifles, and crossbows. 

Thanks to Holosun's LED technology, the battery in this small, compact red dot sight lasts up to 50.000 hours.

What battery does a Holosun 403B take?

The letter 'B' means that the battery compartment is on the right side of the 403B MOA dot in the form of a battery tray. Also, it doesn't run on solar power (no solar panel on top), which is why this model has buttons for the regulation of illumination intensity on the top of sight instead of on the side.

Does Holosun 403B have Shake Awake?

The red dot sight features the ShakeAwake function. When left powered on, the device will go from 'active mode' to 'sleep mode' after a while to prevent unnecessary battery drain. Once moved, it will power back on immediately.

Main features of 403B MOA red dot

  • moa dot reticle: 2 MOA dot

  • red dot sight feature red and green illumination

  • available in black and FDE color

  • sight comes with a low mount and a high mount for lower third co-witness on standard AR platforms

  • Holosun Shake Awake function

  • same mounting platform as Aimpoint Micro devices

  • 12 illumination intensity levels, 2 of them are NVD compatible

  • 403B MOA dot is Parallax free

  • Holosun guarantee 50.000 hours battery life

  • the battery compartment on the right side of the MOA red dot in the form of a battery tray

About the Paralow series

Paralow is one of the red dot sight series made by Holosun. On the outside, these small tube sights are very familiar to the Micro red dot sights made by the famous Swedish red dot sight manufacturing company. The illumination is powered by a CR2032 battery. The click value for the elevation and windage adjustments is 0.5 MOA. These durable red dot sights feature a single-piece housing made out of aluminum. Altogether, there are 12 illumination intensity levels to choose from, 2 of which are NVD compatible. The battery life is 50.000 hours. These are compact but not as small as an open reflex sight.

About the 403B model family

The Holosun 403 MOA dot is one of the model families in the Paralow series. The first number '4' in its name suggests that it features a 2 MOA dot (the user cannot switch to the circle dot reticle as with models that start with number '5'). The second number '0' implies that the product comes with standard accessories (without honeycomb filter, quick-release mount and flip-up lens covers).

Mounting details and footprint on 403B

These Holosun small tube sights come with a high mount for an AR platform (lower 1/3 co-witness) and a low mount for other mounting purposes (such as mounting on a rifle). All models in the Paralow series except the ones with the letter 'A' in their name have the same mounting platform as the Aimpoint Micro devices

For more information about footprint on 403B red dot sight contact us or read our blog post Holosun 403B Footprint

Warranty on Holosun's 403B

The warranty on Holosun red dot is 3 years on the material and on the electronics.

For more information regarding the Holosun symbols, check our blog post.

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Holosun 403B Specifications

Dot sight seriesHolosun Paralow
Made inChina
In production since2018
WarrantyHolosun Elite - 10 years
Click Value 14mm/100m - 1/2MOA
Windage - mrad. 14.53mrad
Windage - MOA.50MOA
Reticle position No
Reticle illumination Yes
Usable at daytime Yes
Automatic Turn Off Yes
Size of Dot.2MOA
Adju. intensityYes
Intensity controlYes
Parallax setting Parallax-free
Length.62 mm
Width.36 mm
Height.41 mm
Working temperature range-30℃~60℃
Power Supply UnitCR2032
Battery lifespan.0h
Filled with No
Lens coatings Fully Multicoated
Tube size/diameter 20 mm
Mounting StandardAimpoint Micro
Mount type - IntegratedFixed mount, Picatinny
Mount length.0mm
Size of windowNo
Dot Sight TypeSmall tube sight
Water proof Yes
Fogproof Yes
Shock proofYes
Type of mount rail Picatinny Mount


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Reviews & Testimonials

Reviews for Holosun 403B

4 reviews
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Great product By
Great red dot for the price. Robust, precise, easy to use. Zeroing was a piece of cake. With the shake awake function the optic is always ready when you touch the rifle. The 2MOA dot is really crispy, you can easily adjust the brightness. The rubber lens cap is a little bit annoying, because it’s quite hard to put on and you can easily lose it. I started with a 100€ red-dot from a different manufacturer which I had to send back, because it was already broken when I took it out of the box. This Holosun was only a little bit more than 200€s, but totally different quality! Amazing product for this price!

(Posted on 11/01/2021)

403B By
Ottimo servizio della Optics-Trade, assistenza sulla spedizione da dieci e lode e molto veloci, GLS un poco meno.
Red dot veramente valido, con 6 colpi ho tarato a 60 metri, molto preciso e intuibile, ora non resta che provarlo su qualche cinghiale. Per ora 10+++ all'ottica e all' azienda.


Excellent service of the Optics-Trade, assistance on shipping by ten and very fast, GLS a little less.
Really good red dot, with 6 shots I calibrated to 60 meters, very precise and intuitive, now I just have to try it on some wild boar. For now 10 +++ optics and company.

(Posted on 05/01/2019)

Good budget red dot. By
Easy to use, good for the price.
No, its not a Aimpoint, but at this price it's a much cheaper option and from the reviews on youtube seems to stand up to some abuse.
Very happy, with the product and the service.

(Posted on 11/08/2017)

Great budget red dot By
I have to say I am really pleased with the quality of the Holosun HS403b. The glass is clear and the 2 MOA dot is quite good. It can be set bright enough to be visible in bright sunlight and it is small enough to allow precision shots.

Zeroing the red dot was quite easy, as it comes from the factory already centered and there is no need to chase it around and get it centered.

All in all, I am more than satisfied with this purchase.

(Posted on 06/01/2017)

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