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Questions & Answers
What is the overall length of this magnifier? Expert Answer

Primary Arms does not provide the overall length for the Primary Arms 3X Red Dot Magnifier GEN III but states it features 1.9" of eye relief, has a 39.37 ft field of view, and weighs 9.1 oz. I would recommend reaching out to Primary Arms directly for more information on the dimensions of this magnifier.

by Ethan, Gear Expert, March 25, 2022
Will this work with a 1x compact prism scope with illumination ACSS CYCLOPS article? Expert Answer

No, magnifiers do not work with prism sights as they shift the point of aim.

by Ethan C., Gear Expert, June 20, 2019
Customer Reviews
Helpful Positive Review
Great for the price. by Big Al, Verified Owner, April 2, 2025
Solid magnifier and flip to side base. Magnifier range finder markings are clear and smooth. The flip to side base is solid. As sturdy as my eotech g45. The magnifier sits behind Holosun Elite 65 MOA Circle 1/3 co- witness used the tallest shim to a...
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1/1 found this helpful
Helpful Positive Review
Does The Job by Keypunch, Verified Owner, May 7, 2025
Excellent little 3x magnifier. Love the Pegasus version with the ranging hash marks. Has a smaller eye box than I'd like, but it's easy to adjust shooting position with a proper turkey neck cheek weld.
1/1 found this helpful
Helpful Positive Review
Best bang for the buck by Stinger601, Verified Owner, July 3, 2017
Primary Arms makes quality products that aren't too expensive, but not cheap low quality either. This magnifier isn't any different and is mid quality and with a good price point. The glass used is of good quality and gives a nice 3X sight picture. I...
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1/1 found this helpful
Helpful Positive Review
Seems like a good 3x magnifier by Dale, Verified Owner, December 15, 2023
This primary arms 3x micro magnifier seems like it will work. Strange thing is, I had to mount it in front of the primary arms 1x micro prism scope. When it was mounted behind the scope I could not see anything, all blurry. Moved it forward and it wo...
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3/5 found this helpful
Helpful Positive Review
Primary arms magnifier by Wild Bill, May 7, 2017
Works well with vortex strikefire 2 red dot. The price was very reasonable and it arrived in five days. Well made and looks sturdy enough for an ar-15. So far so good. Compact size is perfect for mounting on different platforms and calibers
2/2 found this helpful
Helpful Positive Review
Good glass, clear and the unit was solid. Compared to my Eotech magnifier it was rather comparable, minus 400 dollar price tag. I used this and the mount on my LR-308 which I run an Eotech XPS3 works great and the mount is also solid.
4/5 found this helpful
Read All 19 Reviews
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Product Info for Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight

Quickly mount the Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight onto your firearm with or without the help of a gunsmith for the smoothest shot ever. These Red Dot Sight Magnifiers from the inventors at Primary Arms feature a 3X magnifier for increased visibility in low-light and twilight conditions. With an integrated diopter, the Primary Arms Compact 3X Red Dot Magnifier can switch between magnifications without missing a beat or becoming blurry and pixelated. Affordable and ergonomic, the Primary Arms 3X Prism Red Dot Magnifier is the perfect solution for your newest rifle.image

WARNING: California`s Proposition 65

Specifications for Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight:

Manufacturer: Primary Arms
Finish: Matte
Magnification: 3 x
Objective Lens Diameter: 21 mm
Eye Relief: 1.9 in
Weight: 9.1 oz
Field of View, Linear: 39.37 ft at 100 yds
Optical Coating: Fully Multi-Coated
Fabric/Material: Aluminum
Color: Black
Condition: New
Water Resistance Level: Waterproof
Mount Type: Picatinny
Magnification Type: Fixed
Attachment Type: Picatinny

Features of Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight:

  • 3x Magnification
  • 21mm Objective lens diameter
  • 7.0mm Exit pupil
  • 5.3 ounces
  • Compact design

Package Contents:

  • Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight

Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight Orderable Models

List of Orderable Models

  • Primary Arms SLx The SLx 3x21mm Micro Magnifier Red Dot Sight, Black, 510010 , MPN: 510010 , UPC: 818500015826 , Code: 29R-RDM-3XRD-510010
  • Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight, ACSS Pegasus Reticle, Black, 510011 , MPN: 510011 , UPC: 818500015833 , Code: 29R-RDM-3XRD-510011

Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight Unavailable & Discontinued Models

List of Unorderable Models

  • Blemished Demo, Primary Arms SLx 3X Red Dot Magnifier GEN III, Black PA3XGENIII , MPN: BLEM-PA3XGENIII , Code: 29R-RDM-3XRD-PA3XGENIII-DEMO
  • Primary Arms SLx Red Dot Magnifier, 3x, Gen III, No Mount, Black, PA3XGENIII , MPN: 510001 , UPC: 818500010203 , Code: 29R-RDM-3XRD-510001
  • Primary Arms SLx 3X Red Dot Magnifier GEN III w/ Quick Detachable Flip To Side Mounts - Standard Height , MPN: PA3XGENIII-KIT2 , Code: 29R-RDM-3XRD-PA3XGENIII-KIT2
  • Primary Arms SLx 3X Red Dot Magnifier GEN III w/ Quick Detachable Flip to Side Magnifier Mount - 1.75 in. Height , MPN: PA3XGENIII-KIT1 , Code: 29R-RDM-3XRD-PA3XGENIII-KIT1
  • DEMO, Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight, Black, 510010 , MPN: 510010-DEMO , Code: 29R-RDM-3XRD-510010-DEMO
  • USED, Primary Arms SLx The SLx 3x21mm Micro Magnifier Red Dot Sight, Black, 510010 , MPN: 510010-EDEMO , Code: 29R-RDM-3XRD-510010-EDEMO-RE-B
  • DEMO, Primary Arms SLx 3x21mm Micro Magnifier Red Dot Sight, ACSS Pegasus Reticle, Black, 510011 , MPN: 510011-DEMO , Code: 29R-RDM-3XRD-510011-DEMO
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