6 Best Red Dot for Arex Rex Zero 1 in 2026: Mounting & Compatibility

Best red dot for Arex Delta Gen. 2 M setups are more nuanced than many shooters expect because this pistol’s optics-ready system sits in an unusual middle ground between compact and duty-size handgun footprints. The Delta Gen. 2 M offers excellent ergonomics, low bore axis characteristics, and surprisingly good recoil control, but getting the right optic requires careful attention to mounting plates, deck height, screw fitment, and suppressor-height sight compatibility.

I spent considerable time evaluating optics that actually pair well with the Arex slide geometry rather than simply recommending the most popular pistol dots on the market. Window shape, emitter protection, battery accessibility, and footprint compatibility all matter more on this platform because the Delta’s slide width and optic cut dimensions can create either an outstanding co-witness setup or a frustratingly tall mounting arrangement.

Below are the six optics I believe provide the best combination of reliability, mounting compatibility, recoil handling, and real-world usability for the Arex Delta Gen. 2 M in 2026.

---

Quick Summary Table

Product	Best For	Footprint	Window	Battery	Durability	Dot Size	Rating
Holosun 507C	Best Overall	RMR	Large	Side tray	Excellent	2 MOA / MRS	9.6/10
Trijicon RMR Type 2	Hard Use Duty Carry	RMR	Medium	Bottom load	Outstanding	3.25 MOA	9.7/10
Holosun EPS Carry	Concealed Carry	RMSc Modified	Compact enclosed	Side tray	Excellent	2 MOA	9.4/10
Steiner MPS	Closed Emitter Duty	ACRO	Large enclosed	Top load	Outstanding	3.3 MOA	9.5/10
Leupold DeltaPoint Pro	Fast Acquisition	DPP	Extra large	Top load	Very Good	2.5 MOA	9.2/10
Vortex Defender CCW	Budget-Friendly Carry	RMSc	Compact	Top load	Good	3 MOA	8.8/10

---

Top Product List: best red dot for Arex Delta Gen. 2 M

• HOLOSUN 507C
• Trijicon RMR Type 2
• HOLOSUN EPS CARRY
• Steiner MPS
• Leupold Deltapoint Pro
• Vortex Defender CCW

---

HOLOSUN 507C

The 507C remains my preferred balance of durability, value, mounting flexibility, and usability on the Arex Delta Gen. 2 M platform.

Specs

• Footprint: RMR
• Reticle: 2 MOA dot + 32 MOA circle
• Battery: CR1632 side tray
• Window Size: Large
• Housing: 7075 aluminum
• Brightness: 10 daylight + 2 NV

Pros

• Excellent value-to-performance ratio
• Side battery tray prevents rezero issues
• Crisp reticle with minimal bloom
• Strong aftermarket plate support

Cons

• Slight green lens tint
• Buttons feel small with gloves
• Open emitter can collect debris

The 507C pairs exceptionally well with the Delta Gen. 2 M because the optic width visually matches the slide dimensions without overhanging excessively. I noticed very little parallax shift inside realistic defensive distances, especially during rapid target transitions between 7 and 20 yards.

The deck height works well with suppressor-height irons when paired with a proper RMR plate. I strongly recommend steel mounting plates instead of polymer adapters because the Delta’s recoil impulse is snappy enough to expose weak hardware over time.

The side battery tray is one of the optic’s biggest practical advantages. I dislike removing pistol optics for maintenance because every reinstall introduces torque variation and potential zero shift. The 507C completely avoids that issue.

Online discussions consistently praise the optic’s reliability under sustained recoil cycles. Users also mention strong durability during slide-mounted use on compact pistols. The multi-reticle system remains divisive, though. Some shooters love the large acquisition circle, while others prefer a clean single-dot configuration.

Mounting is straightforward with a standard RMR-pattern plate. Most aftermarket Delta Gen. 2 M optic systems already support this footprint directly.

➡️➡️➡️ Explore User Feedback and Current Pricing on Amazon

---

Trijicon RMR Type 2

The RMR Type 2 is still the benchmark for slide-mounted pistol optic durability in hard-use environments.

Specs

• Footprint: RMR
• Dot Sizes: 1 MOA, 3.25 MOA, 6.5 MOA
• Battery: CR2032 bottom load
• Housing: Forged aluminum
• Waterproof: 20 meters
• Weight: 1.2 oz

Pros

• Exceptional recoil durability
• Extremely rugged housing design
• Excellent sealing against moisture
• Proven duty track record

Cons

• Bottom battery compartment
• Noticeable blue lens tint
• Window smaller than competitors

The forged housing design genuinely matters on reciprocating pistol slides. The RMR survives abuse that damages many competing optics, especially during repeated one-handed slide manipulations or impact against barricades.

On the Arex Delta Gen. 2 M, the optic sits low enough to maintain a clean presentation angle without making the gun feel top-heavy. The deck height supports a usable lower-third co-witness depending on the chosen plate system.

Parallax performance remains excellent. During movement drills, I found the dot stayed visually stable even when my presentation angle was imperfect. That matters on compact defensive pistols where presentation consistency can vary under stress.

The button design is also underrated. They are stiff enough to avoid accidental activation while still remaining usable with gloves. Some newer optics prioritize soft tactile buttons, but those often activate unintentionally during concealed carry.

The biggest drawback is still the bottom-mounted battery. You must remove the optic for replacement, which means verifying torque specs and rezeroing afterward. For a duty-grade optic, that compromise remains surprisingly outdated.

Community feedback continues to reinforce the RMR’s reputation for reliability under recoil, weather exposure, and extended carry use. Many shooters still compare every pistol optic directly against it.

The Delta Gen. 2 M requires a dedicated RMR-pattern mounting plate, but compatibility is now widely available.

➡️➡️➡️ Explore User Feedback and Current Pricing on Amazon

---

HOLOSUN EPS CARRY

The EPS Carry is the optic I recommend most often for concealed carry-focused Arex Delta builds.

Specs

• Footprint: RMSc modified
• Reticle: 2 MOA dot
• Battery: CR1620 side tray
• Housing: Enclosed emitter
• Waterproof: IPX8
• Brightness: 8 daylight + 2 NV

Pros

• Fully enclosed emitter
• Excellent weather protection
• Minimal lint intrusion during carry
• Lightweight design

Cons

• Smaller viewing window
• Narrower field of view
• Requires adapter considerations

Closed-emitter optics make enormous practical sense on carry pistols. Open emitters can become obstructed by sweat, lint, rain, or carbon buildup surprisingly quickly. The EPS Carry solves that problem without becoming excessively bulky.

On the Arex Delta Gen. 2 M, the optic maintains excellent concealability while still giving enough window size for fast dot acquisition. I found the presentation extremely natural after only a few practice sessions.

The lens coatings are well controlled with less distracting tint than older Holosun models. Window distortion near the edges is also minimal. Some compact optics introduce fisheye distortion around the perimeter, but the EPS Carry stays relatively clean.

The side battery tray again improves long-term usability. I also appreciate the recessed adjustment controls because they reduce accidental brightness changes during carry.

One thing buyers need to understand is footprint compatibility. The EPS Carry uses a modified RMSc-style footprint, so you must confirm the exact adapter plate for the Arex system. Some plates slightly elevate deck height more than ideal.

Online user feedback heavily favors the optic’s enclosed design and carry practicality. Many shooters moving from traditional RMR optics report improved reliability during daily appendix carry.

For shooters prioritizing concealed carry over maximum window size, this is one of the most balanced optics currently available.

➡️➡️➡️ Explore User Feedback and Current Pricing on Amazon

---

Steiner MPS

The Steiner MPS is one of the toughest enclosed pistol optics currently available for duty-oriented use.

Specs

• Footprint: ACRO
• Dot Size: 3.3 MOA
• Battery: CR1632 top load
• Housing: Fully enclosed
• Waterproof: 10 meters
• Construction: Aluminum

Pros

• Outstanding durability
• Large enclosed viewing area
• Top-loading battery
• Excellent sealing performance

Cons

• Heavier than open emitters
• Bulkier carry profile
• More expensive mounting ecosystem

The MPS handles recoil exceptionally well on the Arex platform. Its enclosed design protects the emitter from debris while maintaining a surprisingly generous viewing window.

I particularly like the optic’s top-loading battery compartment because it eliminates unnecessary optic removal. The cap threading also feels more refined than some competing enclosed systems that can cross-thread under rushed maintenance.

The glass quality is excellent with relatively neutral tint characteristics. During bright outdoor shooting, the dot remained crisp without excessive flare or starburst distortion.

The optic is heavier than compact open emitters, though. You absolutely notice additional slide mass during rapid recoil cycles. Fortunately, the Delta Gen. 2 M’s recoil characteristics remain manageable enough that the extra weight actually smooths slide impulse slightly.

Parallax shift is minimal across the entire usable window. I also found the larger enclosed window easier to track during recoil than smaller enclosed optics.

Online discussions frequently compare the MPS against the Aimpoint ACRO P-2. Many users prefer the Steiner’s larger field of view and cleaner glass despite slightly reduced battery life.

The mounting situation requires an ACRO-compatible plate. Those plates are generally thicker and taller than RMR systems, so expect a slightly elevated optic height and potentially different suppressor sight requirements.

This is an outstanding option for shooters prioritizing environmental sealing and hard-use durability.

➡️➡️➡️ Explore User Feedback and Current Pricing on Amazon

---

Leupold Deltapoint Pro

The DeltaPoint Pro remains one of the fastest pistol optics for rapid sight acquisition.

Specs

• Footprint: DPP
• Dot Sizes: 2.5 MOA or 6 MOA
• Battery: CR2032 top load
• Window: Extra large
• Housing: Aluminum
• Weight: 1.95 oz

Pros

• Huge viewing window
• Very fast target acquisition
• Excellent glass clarity
• Easy battery access

Cons

• Taller deck height
• Larger carry footprint
• Slightly exposed front lens

The oversized window is the defining feature here. On the Arex Delta Gen. 2 M, the DeltaPoint Pro feels incredibly fast during transitions because the sight picture is forgiving even with imperfect presentations.

The glass quality is excellent with very little tint compared to many competitors. I also noticed less perceived tunnel effect during movement drills. The optic simply feels open and easy to track.

However, the taller deck height changes the presentation angle slightly. Shooters accustomed to low-mounted RMR optics may initially overshoot the dot during draws until muscle memory adjusts.

The battery compartment design is excellent. Top-loading access is simple, secure, and convenient. I also like the larger brightness adjustment button because it remains easy to manipulate with gloves or cold hands.

Durability is solid overall, although I still consider the RMR and MPS slightly stronger for extreme abuse. The front lens area on the DeltaPoint Pro feels somewhat more exposed during impact scenarios.

Community feedback overwhelmingly praises the optic’s speed and visibility. Competitive shooters especially appreciate the large window and forgiving sight picture during rapid fire strings.

The footprint requires a dedicated DeltaPoint Pro mounting plate for the Arex Delta Gen. 2 M. Once properly mounted, the optic delivers one of the cleanest shooting experiences available.

This section of the best red dot for Arex Delta Gen. 2 M discussion comes down to whether you prioritize speed or maximum compactness.

➡️➡️➡️ Explore User Feedback and Current Pricing on Amazon

---

Vortex Defender CCW

The Defender CCW offers surprisingly strong performance for shooters wanting an affordable concealed-carry optic.

Specs

• Footprint: RMSc
• Dot Size: 3 MOA
• Battery: CR1632 top load
• Housing: ShockShield polymer insert
• Waterproof: Yes
• Brightness: 10 settings

Pros

• Excellent value
• Lightweight carry profile
• Good tactile controls
• Strong warranty support

Cons

• Smaller window
• Not duty-grade durable
• Slight edge distortion

The Defender CCW integrates well with slimmer concealed carry configurations on the Arex Delta Gen. 2 M. The lower weight keeps slide cycling balanced while preserving a compact carry profile.

I was pleasantly surprised by the button tactility. Many budget optics use mushy controls that become frustrating with gloves, but the Defender’s controls provide positive feedback.

The glass clarity is respectable for the price class. There is some edge distortion around the outer perimeter, though it rarely affects practical shooting. The dot itself remains crisp across most brightness settings.

Recoil handling was also better than expected. During extended range sessions, the optic maintained zero without visible flicker issues. Still, I would not rank it alongside premium duty optics for severe abuse or professional use.

The top-loading battery compartment simplifies maintenance considerably. Battery cap design feels secure with less risk of stripping than some cheaper optics in this category.

Online user feedback generally highlights strong value, straightforward operation, and Vortex’s warranty support. Many shooters consider it an ideal entry-level carry optic.

Mounting requires an RMSc-compatible plate, which helps keep deck height lower than many full-size optics. That translates into a more natural co-witness relationship with backup irons.

For budget-conscious shooters wanting a capable carry-ready optic, this remains one of the better values available.

➡️➡️➡️ Explore User Feedback and Current Pricing on Amazon

---

How I Tested / Evaluation Criteria

Parallax

Parallax performance matters more on compact defensive pistols because imperfect presentations happen under stress. I evaluated each optic during off-axis shooting, rapid transitions, and awkward presentation angles to determine how stable the dot remained inside the viewing window.

Optics with excessive perceived drift become slower during dynamic shooting. The best performers maintained consistent point-of-impact behavior even when the dot approached window edges.

Co-Witness / Deck Height

Deck height strongly influences presentation consistency and backup iron usability. I evaluated how naturally each optic aligned during draws while also checking lower-third co-witness compatibility.

Some optics technically fit the Arex platform but sit unnecessarily tall because of adapter thickness. That additional height can noticeably alter presentation mechanics.

Durability

Slide-mounted pistol optics endure constant acceleration forces. I evaluated housing rigidity, sealing quality, lens protection, and screw retention characteristics.

Closed-emitter optics generally performed better in dirty environments, while forged housings consistently resisted abuse more effectively than lightweight cast designs.

Battery Performance

Battery accessibility matters for long-term ownership. Top-loading and side-loading systems dramatically simplify maintenance compared to bottom-mounted designs.

I also evaluated brightness stability, auto-adjust behavior, and low-battery warning consistency.

Brightness Range

A carry optic must function in direct sunlight while remaining usable in low-light environments. I tested bloom behavior, emitter crispness, and night vision compatibility where applicable.

Several optics became excessively starburst-prone at higher brightness levels, especially for shooters with mild astigmatism.

Glass Quality

Lens tint, edge distortion, and overall clarity significantly affect shooting comfort. I evaluated color neutrality, glare management, and distortion near the outer edges of each viewing window.

The best optics balanced reflective coatings without introducing excessive blue or green tint.

Controls Ergonomics

Button placement matters more than many shooters realize. I tested each optic while wearing gloves and during rapid manipulation drills.

Soft buttons can accidentally activate during carry, while overly stiff controls become frustrating during brightness adjustments.

Mounting Ecosystem

The Arex Delta Gen. 2 M requires careful footprint planning. I evaluated adapter availability, screw compatibility, aftermarket support, and overall mounting stability.

RMR-pattern optics currently offer the broadest support ecosystem for this pistol platform.

---

How to Choose the Right Red Dot for This Gun

Choosing the correct optic for the Arex Delta Gen. 2 M starts with understanding your intended role. A concealed carry setup benefits from very different characteristics than a duty-oriented or competition-focused configuration.

If concealment is your priority, compact enclosed emitters like the EPS Carry make the most sense. They resist lint and moisture while minimizing printing during appendix carry. Smaller optics also preserve slide balance and reduce bulk.

For hard-use defensive roles, durability should dominate your decision. The Trijicon RMR Type 2 and Steiner MPS both excel because they survive prolonged recoil cycles, harsh weather exposure, and physical abuse better than most alternatives. Enclosed emitters additionally protect the diode from environmental contamination.

Window size also matters considerably. Larger windows like the DeltaPoint Pro improve target acquisition speed and forgiveness during imperfect presentations. However, those optics often increase deck height and printing during concealed carry.

Mounting compatibility is another critical factor. The Arex platform does not universally support every footprint directly. RMR-pattern optics currently provide the strongest aftermarket plate support and easiest sourcing. ACRO and DPP footprints often require taller or more specialized mounting systems.

Battery access should not be ignored either. Side-loading and top-loading systems simplify maintenance while preserving zero integrity. Bottom-mounted batteries remain durable but less convenient for practical ownership.

Shooters with astigmatism should carefully evaluate emitter crispness and lens tint. Some optics produce more bloom or flare depending on eye characteristics.

Finally, avoid choosing purely by brand reputation. Some premium optics excel in durability but compromise heavily on window size or maintenance convenience. Others prioritize speed but sacrifice ruggedness.

The ideal setup balances concealment, durability, mounting simplicity, and shooting speed based on how the pistol will actually be used.

---

FAQs

Does the Arex Delta Gen. 2 M use an RMR footprint?

No. The pistol uses an optics-ready system requiring adapter plates for most popular footprints including RMR, RMSc, ACRO, and DeltaPoint Pro.

Are enclosed emitters worth it for concealed carry?

Yes. Enclosed emitters resist lint, moisture, and debris significantly better than open-emitter designs during daily carry.

Which optic gives the lowest deck height?

RMSc-pattern optics generally sit lowest on the Arex platform because of their slimmer dimensions and thinner adapter requirements.

Can I co-witness standard-height irons?

Usually no. Most optics require suppressor-height sights to achieve usable co-witness alignment.

What is the most durable option overall?

The Trijicon RMR Type 2 and Steiner MPS remain the strongest overall performers for extreme-duty use.

---

Conclusion

The best red dot for Arex Delta Gen. 2 M ultimately depends on whether your priorities lean toward concealed carry, duty durability, or maximum shooting speed. After extensive evaluation, I believe the Holosun 507C delivers the strongest overall balance for most shooters because it combines excellent reliability, practical battery access, broad mounting support, and outstanding real-world usability on the Arex platform.

For dedicated duty use, the Trijicon RMR Type 2 and Steiner MPS remain exceptional. For concealed carry, the EPS Carry offers one of the smartest enclosed-emitter solutions available today.

No matter which optic you choose, proper mounting hardware, correct screw torque, and reliable adapter plates matter just as much as the optic itself. A well-mounted mid-tier optic will always outperform a poorly mounted premium sight.

Sources referenced include manufacturer technical specifications, user durability reports, mounting footprint documentation, and long-term community feedback.