When Viridian reached out with an offer to review the new Viridian RFX42 Green Dot, I was pretty stoked. The RFX42 is a compact, enclosed emitter green dot sight, commonly referred to as a “mailbox” on most enthusiast sites. While I have plenty of experience with compact optics, I haven’t used this style. And I happened to have an optics-ready Sig which uses the Shield RMSc footprint. A perfect match, so I had them send it. So I could send it.
Quick Answer: Is the Viridian RFX42 Worth It?
The Viridian RFX42 Green Dot is worth considering if you want a compact enclosed-emitter optic for a carry pistol, micro-compact pistol, or optics-ready handgun with a Shield RMSc footprint. It gives you a protected emitter, a bright 3.5 MOA green dot, INSTANT-ON® motion activation, and a lightweight 0.9-ounce design that works well on smaller pistols. Compared to an open-emitter optic like the Viridian RFX15, the RFX42 makes the most sense for shooters who carry daily and want extra protection from lint, dust, rain, and debris.
Viridian RFX42 Green Dot Design & Build Quality
The Viridian RFX42 Green Dot gives shooters a compact, enclosed-emitter aiming solution for carry pistols and smaller optics-ready handguns. Out of the box, it feels well-built with a CNC-machined aluminum housing, matte black finish, and compact footprint. At just under an ounce in weight, it’s impressively light, making it a natural fit for concealed carry pistols.
The standout feature of the Viridian RFX42 Green Dot is its closed emitter system, which protects the emitter from debris and moisture. Unlike the small reflex sights many of us have used for years, the RFX42 fully encloses the emitter. No need to worry about lint, dirt, or wayward raindrops blocking your emitter and rendering it useless. For a carry optic, that added protection makes a lot of sense.
The optic is IPX6 waterproof and shockproof, built to withstand both the elements and recoil. It feels solid without coming off as bulky, and the Shield RMSc footprint means it’s compatible with a wide variety of optics-ready pistols.
Optical Performance
The RFX42 uses a 3.5 MOA green dot. Since the human eye is more sensitive to green than red, this makes it easier to pick up quickly. Coupled with the size of the dot, it’s quick to pick up in daylight, yet still fine enough for some “precision” shooting at longer defensive distances.
Brightness & Settings
With 10 brightness settings (8 daylight, 2 night vision compatible), the optic works well in bright outdoor conditions as well as low-light environments. Adjustments are simple and responsive.
Viridian RFX42 Technology & Features
Viridian’s Motion-Activated INSTANT-ON® Technology is a highlight. The sight powers on with motion and shuts off automatically when not in use. This feature helps extend the already impressive 28,000-hour battery life on a single CR1620 (included). That’s over three years of continuous use, but there is no mention of which light level that would be. I’d still swap the battery once a year to be on the safe side.
Lens & Clarity
The fully multi-coated 21mm x 17mm aspherical lens provides excellent clarity and light transmission. While this small window might make it seem difficult to use, that bright green dot absolutely pops. I can pick it up just about instantly. The sight picture is sharp, with minimal distortion, making it reliable for both training and defensive use. Unlike most red dots, I see a lot less bloom from a green dot with my astigmatism when I’m not wearing my glasses.
Ideal for Concealed Carry
At just 0.9 oz, the Viridian RFX42 Green Dot doesn’t weigh down the slide, and its compact dimensions make it ideal for slim carry, subcompact, and micro-compact pistols. Viridian clearly designed it with everyday carry in mind. The Shield RMSc footprint ensures compatibility with popular models like the Sig P365, Springfield Hellcat, Ruger MAX-9, Taurus TX22 Compact and GX4 TORO, as well as others.
The image below shows how much dust and lint it collected after just a few days of carry. This had zero effect on the visibility of the dot. But imagine all that falling inside a traditional open-emitter optic. A closed emitter is clearly a better design when it comes to daily carry.
Viridian RFX42 Green Dot Installation
The packaging includes a variety of screws in different sizes, along with a tool for both installation and adjustment, plus battery replacement. It’s a very complete installation kit; you just need a pistol compatible with the Shield RMSc footprint and a few minutes of your time.
Interestingly, installing on a Sig P365 requires the removal of the rear sight, which is built into the optics mount cover. Yet a much less expensive pistol like the Ruger MAX-9, which has better sights to begin with, retains the rear sight, and it co-witnesses with the RFX42. That’s just an issue I have with Sig, and nothing to do with Viridian. But after removing the cover, it’s a matter of carefully tightening two screws, and the optic is installed. I used a red magnetic laser on the barrel for a quick zero.
Range Time with the Viridian RFX42
At the range, the green dot is easier to pick up than irons, and you just place it on your target. No need to align sights as you would with traditional irons. The unlimited eye relief means you don’t need to be perfectly aligned to see the dot, which speeds up follow-up shots. I ran some basic drills at defensive distances and tried some longer shots too. Two buttons on the side control brightness up or down, and they are sized and spaced for ease of use. Each tap responds with a tactile and audible click.
There’s no question that I can shoot marginally faster with this setup. All that practice with rimfire meant very little adjustment time for me, but if you haven’t used this type of sight, be prepared to put in some practice time. I should also note that it rode in the plastic door pocket of a 4×4 for many range trips. That exposed it to some rough and rutted dirt trails at speed. Not your typical storage, but that’s part of the review process. And it held up just fine despite being treated much worse than it would normally be.
Viridian RFX42 vs RFX15
The RFX42 and RFX15 both make sense for compact carry pistols, but they are not the same optic. The Viridian RFX15 is an open-emitter green dot with the same general footprint family, a lower profile, and a more traditional reflex sight layout. It is simple, compact, and easy to carry.
The RFX42 is the better choice if you want an enclosed-emitter optic for daily carry. It adds a little more housing around the emitter, but that protection matters if the pistol rides inside a holster every day and may collect dust, lint, rain, or debris. If you want the smallest, simplest setup, the RFX15 still makes sense. If emitter protection is the priority, the RFX42 is the one I would choose.
Who the Viridian RFX42 Is For
The Viridian RFX42 is for shooters who want a compact enclosed-emitter green dot for a carry pistol or smaller optics-ready handgun. It is especially well suited for pistols that use the Shield RMSc footprint, including common micro-compact and slim carry pistols.
It is probably not the optic I would choose for a full-size competition pistol, pistol-caliber carbine, or offset rifle setup. For those uses, I would rather have a larger window. But for concealed carry, daily carry, and compact optics-ready pistols, the RFX42 makes a strong case for itself.
Viridian RFX42 Green Dot Sight Pros & Cons
Pros
- Lightweight and compact design (0.9 oz)
- Enclosed emitter for better protection from dust, lint, moisture, and debris
- Crisp 3.5 MOA green dot for fast target acquisition
- Motion-Activated INSTANT-ON® Technology
- Up to 28,000 hours of battery life
- Shield RMSc footprint for wide pistol compatibility
- IPX6 waterproof and shockproof
- 8 daylight and 2 night-vision compatible settings
- Bright green dot that stayed visible in Utah desert sunshine
Cons
- Runs on a CR1620 battery, which is less common than CR2032
- Slightly higher MSRP ($339) compared to some budget optics
- Smaller window than full-size optics, which is expected for a compact carry optic
- As someone who doesn’t usually use an optic on his carry pistol, I found that I smudged the front lens often. That’s a training issue, but one to be aware of.
Frequently Asked Questions About the Viridian RFX42
What footprint does the Viridian RFX42 use?
The Viridian RFX42 uses the Shield RMSc footprint. That makes it compatible with many slim, compact, and micro-compact optics-ready pistols.
Is the Viridian RFX42 an enclosed-emitter optic?
Yes. The RFX42 is a compact enclosed-emitter green dot sight. The enclosed design helps protect the emitter from lint, dust, rain, and debris.
Is the Viridian RFX42 good for concealed carry?
Yes. The RFX42 is lightweight, compact, and designed around carry pistols. The enclosed emitter is especially useful for daily carry because it helps keep the aiming system protected inside a holster.
Is the Viridian RFX42 better than the RFX15?
It depends on what you want. The RFX15 is smaller and more traditional as an open-emitter reflex sight. The RFX42 adds the enclosed emitter, which makes it more appealing for daily carry and rougher conditions.
What battery does the Viridian RFX42 use?
The RFX42 uses a CR1620 battery. Viridian lists battery life at up to 28,000 hours, though I would still replace it annually for carry use.
Is the Viridian RFX42 a red dot or green dot?
The RFX42 is a green dot sight. The 3.5 MOA green dot was easy to pick up quickly and stayed visible in bright outdoor conditions.
Does the Viridian RFX42 have motion activation?
Yes. The RFX42 uses Viridian’s Motion-Activated INSTANT-ON® Technology, so the sight powers on with motion and shuts off automatically when not in use.
Is the Viridian RFX42 good for astigmatism?
For my eyes, the green dot showed less bloom than many red dots when I was not wearing glasses. Astigmatism varies by shooter, but this was one of the advantages I noticed.
Final Thoughts on the Viridian RFX42 Green Dot
The Viridian RFX42 delivers on its promise of durability, clarity, and speed in a compact, closed-emitter package. It’s lightweight enough for daily carry, rugged enough for adverse conditions, and smartly designed with features like INSTANT-ON® and long battery life. It’s probably going to earn a spot in my EDC rotation.
For shooters who want a reliable green dot sight for their concealed carry or optics-ready pistol, the RFX42 is a strong contender in its class. Find it on the Viridian Weapon Technologies website.
The RFX42 offers the same footprint family as Viridian’s RFX15 but in an enclosed-emitter format, for those prioritizing reliability. So if you’re not into the “mailbox”, check out my review of the Viridian RFX15.
As always, I’d like to thank Viridian for sending out the Viridian RFX42 for my testing and evaluation ahead of its release.