If there’s one trend experiencing steady growth, it’s red-dot love for carry guns. There was a time when red-dot users were viewed as gear-dependent. If you used a red dot, you must not be able to run iron sights, right? Wrong.

Today it’s widely understood that red dots are fantastic tools for shooters. And there are a multitude of red-dot options on the market, each offering pros and cons and suiting various needs. If you’re in the market for an ultra-compact micro reflex sight from a major manufacturer, take a closer look at the SIG ROMEOZero 1x18mm Micro Reflex Sight.

SIG ROMEOZero Specifications

The SIG ROMEOZero 1x18mm Micro Reflex Sight has features that set it apart from many red dots permeating the market. Perhaps the most noteworthy difference is its housing. Unlike many red dots, the ROMEOZero has a lightweight polymer housing. SIG lists it as made from weapons-grade textured polymer for the body and the trademarked SpectraCoat HD polymer system for the lens. (Yes, both the housing and lens are made from polymer.) This makes it lighter in weight and a bit less bulky overall. It also means it may be more scratch-resistant and durable. (According to SIG, this lens is 10 times more impact-resistant than a standard glass lens.) It weighs in at 0.4 ounces (14 grams).

The ROMEOZero Micro Reflex Sight

The ROMEOZero Micro Reflex Sight.

Lens Diameter: 24mm
Overall Length: 1.6 inches
Overall Width: 0.93 inches
Height: 0.93 inches
Weight: 0.4 ounces

At 1.6 inches long, 0.93 inches high and 0.93 inches wide, this is a streamlined little sight. My review version of the ROMEOZero was shipped mounted to a SIG P365XL. This model of gun has the slide already milled to fit the sight, and it does indeed fit sleekly with the shape and lines of the gun. The textured finish is aesthetically appealing and matches the textured grips of the P365XL. One pro of having a textured sight for your carry gun is it’s easier to hold onto while zeroing the dot or installing the sight itself. This may seem like a small thing, but those tiny details really do matter.

This is a motion-activated red dot. It senses movement and turns on. It is then supposed to shut down when it no longer senses movement. The reticle itself is a 3 MOA with eight daytime-bright illumination settings. SIG designed the ROMEOZero with an LED emitter for a sharper, more vivid red dot. Magnification is 1X. It takes a CR1632 battery and is listed as having a 20,000-hour run time and 10-year battery life. This is a parallax-free red dot.

Installing the Sight

One of the most important features of a red dot is whether it can be zeroed easily and stay zeroed with use. My review sight arrived already installed. Although I had already decided to take it off and install it myself, I wanted to check it out first. Out of the box, it was indeed securely installed. But I quickly discovered the battery it shipped with was dead. It could have been because it’s motion-activated and turned itself on endlessly during shipping.

Installation was easy. SIG optimized the ROMEOZero for compatibility with pistols with slim slide profiles.

Removing the ROMEOZero was simple and made easier because SIG includes a pair of Allen wrenches. The larger-diameter hex is meant to remove/install the screws holding the sight to the slide. The sight was off the gun in a matter of moments. Once I had it off, I discovered a downside: The battery is bare against the slide and not held in place within the sight by any type of prong or retention part.

SIG instructs you to hold the battery in place with one finger while installing it on the slide. That’s not technically possible (it has to go against the slide, after all). Holding the gun upside down so the battery remains in place in the sight will work — and so does carefully fitting the sight on top of the battery by basically wiggling it into place. Whether or not this is a big deal may be a matter of preference, but it also brings up the question of water resistance. If you run this sight in the rain, will it keep going or will moisture immediately reach the battery and interfere with the contact points?

ROMEOZero at the Range

With a fresh battery in place and the sight screwed back, it was time to zero. The skinnier hex was meant for zeroing and did its job just fine. Zeroing was as expected for a red dot; the dot was off to one side and took a moment to locate and move over, but it was easy. One pro of this model is you can co-witness the front iron sight on the P365XL with it. That means if your red dot does go down, you’ve still got that front sight going for you — and using the front sight to co-witness can speed up target acquisition, among other things.

The dot has excellent clarity.

The ROMEOZero’s dot stayed zeroed through 250 rounds of 9mm in one range session, which is a promising start. It also remained in place during some minor bumps and shakes. To change the brightness, push a tiny raised button located immediately behind the polymer lens. You can press the button with your fingertip, but you have less risk of smudging or otherwise mussing the lens if you use the tip of one of the included hex wrenches. This dot does have excellent clarity, making it easy to acquire, especially when you’re performing timed drills. And the movement of the draw stroke was sufficient to turn it on. Using a red dot on your carry gun takes some practice — just like any gun skill. It is well worth the effort of learning.

There’s minimal overhang with this sight, meaning a much lower risk of snagging and catching than the somewhat oversized brands that do stick out on either side of the gun’s slide. A number of holsters are available specifically cut for the ROMEOZero, so you won’t have any problems finding a good carry holster if your pistol has one mounted.

Bottom Line

The SIG ROMEOZero 1x18mm Micro Reflex Sight makes a nice aesthetic match for the SIG P365XL and holds zero nicely with use. It’s easy to zero, the various brightness levels are useful, and it doesn’t catch on clothing when drawing or holstering. With a $259.99 MSRP, the ROMEOZero fits well in many gun budgets and leaves room for a good red-dot class too. It performs within its price point and does it with style. SIG has done well in the electro-optics market since it first tossed its optics hat in the ring back in 2014, and the company continues to put the work into designing and manufacturing use-specific, shooter-friendly models.