Estimated reading time: 8 minutes
The more I use clip-on thermals, the more I appreciate what they bring to the table: fast deployment, day-to-night flexibility, and no need to re-zero when you switch from daylight to nighttime operations. The new Armasight Operator 640 1–4x35mm is a rugged, no-compromise clip-on system designed for professional-level use. After spending time behind it, I’m convinced this unit deserves a spot in serious kits.
Table of contents
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The Operator 640
For those unfamiliar, a clip-on thermal like this doesn’t replace your scope. It mounts in front of it, using your day scope’s reticle for aiming. That means you keep your riflescope zero, stay versatile in daylight, and simply deploy thermal when needed without swapping optics or re-zeroing. When done right, it’s the best of both worlds.
The Operator 640 does it right.
Operator 640 Specs That Matter
From Armasight’s site:
- Thermal Sensor: 640×512, 12μm, <40 mK NETD
- Optical Magnification: 1x native (4x digital)
- Lens: 35mm germanium
- Display: 1024×768 HD OLED
- Detection Range: ~1300 yards (man-sized target)
- Mount: ADM QD (1.5” above rail height)
- Recoil Rating: Up to .50 BMG
- Power: Dual CR123A batteries (~4 hrs runtime)
- Weight: 1.5 lbs
- Operating Temp: -40°F to 122°F
- Housing: Rugged, sealed aluminum alloy
- Color Palettes: White Hot, Black Hot, Rainbow, Target, Sepia
- Recording: Internal photo and video storage
- Price: ~$3,999 MSRP
- Made in the USA (majority components)
In the Field: What I Learned about the Operator 640
1. Mounting is Easy & Solid
The included ADM quick-detach mount is top-tier. It clicks right onto any Picatinny rail and sets the optic at exactly 1.5” centerline. Perfect for LPVOs or standard AR builds. Mounting and unmounting takes seconds, with rock-solid repeatability. Recoil rating up to .50 BMG means no worries about banging it up in the field. Many thermals aren’t rated below -4°F or above 110°F, which could be problematic in extreme conditions. I want to point out that the Operator is rated for -40°F to 122°F and is built tougher than many of the other thermals on the market.
2. It Just Works with Your LPVO
This unit pairs exceptionally well with a 1–6x or 1–10x LPVO, especially those with adjustable diopters. The clip-on itself doesn’t have diopter focus, so you rely on your day scope’s adjustments for a clean image. Through the scope, it’s crystal clear, and your existing reticle stays in play for all aiming and holdovers.
3. Operator 640 Performance is Legit
With a 35mm germanium lens, 12-micron sensor, and <40 mK NETD sensitivity, detection and target clarity are excellent. Armasight says you’ll detect a man-sized target at 1300 yards, and in the right conditions, I believe that’s true. It’s not going to perform as well as some dedicated thermal scopes, but that’s expected. Clip-ons trade a little resolution for huge versatility.
4. Ergonomics Are Thoughtful
The focus wheel is at the end of the objective and is relatively easy to manipulate while mounted. Menu buttons are low-profile, tactile, and intuitive. No guessing which one does what in the dark. I can’t tell you how often I’ve fumbled with button clusters on other optics. Not here.
5. Recording is Internal (But No Reticle)
Video and photo recording are built in. But here’s a critical note for folks new to clip-ons. You won’t see your reticle in the recordings because it lives in your day scope, not the thermal. That’s not a bug. It’s just how clip-ons work. You aim and shoot using the day optic’s reticle.
6. Zeroing & Boresighting is Easy
The Operator 640 includes a visible internal reticle overlay you can use to boresight and match your POI. Once you know where your bullet’s hitting, just move the clip-on’s display to center that impact. Simple and smart.
7. Color Palettes & Menus
Cycle through white hot, black hot, rainbow, target mode, sepia, and more with a long press. There are also multiple scene modes like Forest, Detect, Sky, and Sea to tune performance based on your environment. The menus are responsive and logical.
8. Operator 640 Bonus Features
- Built-in digital compass and cant indicator
- USB port for external battery packs or file transfer
- Accessory rail for a red dot or laser
- Fast startup time
- Weather-resistant build quality
Who Is This For?
While this will absolutely work for predator hunters or hog guys, the Operator 640 really shines in tactical or emergency-use roles. Whether you’re prepping for contingencies or clearing a property without an IR signature, the flexibility of popping it on or off your existing rifle makes it extremely practical.
Thermals aren’t great for clearing houses or CQB. They’re for people who need exceptionally good detection capability, target ID, and no light signature. With zero IR emission, thermal keeps you completely passive.
I want this kind of unit in a Faraday bag in my safe, ready to go in a bad scenario. It’s rugged, fast, flexible, and doesn’t require me to rebuild a rifle platform or dedicate a gun to night-only work.
READ MORE HERE: Two New Thermals From Nocpix – Full Video Review
Armasight Operator 640 Final Verdict
The Armasight Operator 640 is a professional-grade thermal clip-on that delivers serious performance without overcomplicating anything. It mounts fast, shoots true, and records internally, all while letting you keep your favorite LPVO.
Pros:
- Excellent image quality and detection range
- U.S.-made components and recoil-tested to .50 BMG
- Simple, rugged, and intuitive
- Easy boresighting and menu navigation
- Seamless day-to-night integration
- Affordable for the performance class ($4,000 MSRP)
Cons:
- No diopter for standalone viewing (needs day optic)
- CR123 battery runtime is ~4 hours (carry spares or add external pack)
- No reticle in recordings (inherent to all clip-ons)
If you’re running an LPVO or traditional scope and want to add thermal capability without ditching your daytime glass, or you want a dead-simple contingency optic, the Operator 640 deserves serious consideration.
More Info & Specs: Armasight Operator 640 Clip-On
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As the Editor-in-Chief of GunsAmerica, Hunt365, Decoding Darkness, and Suppressor Academy, True Pearce brings a rare blend of legal expertise, competitive shooting credentials, and deep hunting knowledge to the forefront of the firearms world. A former professional sponsored 3-Gun and Multigun competitor with multiple championships and titles, True’s shooting career began in long-range and tactical sniper matches—and he still burns powder in precision competitions, now branching into Hunter NRL.
A certified firearms instructor who has trained over 10,000 students face-to-face, True has also served on both sides of the courtroom as an attorney and currently as an elected Prosecuting Attorney. He has prosecuted and defended high-profile self-defense and firearms cases, giving him a unique, real-world perspective on the Second Amendment.
Outside the courtroom and off the range, True is a true western outdoorsman. A lifelong hunter and rancher, he rides and hunts off his own string of horses and pack animals, chasing elk, mule deer, wolves, coyotes, and anything else in season. He’s a longtime reloader, producing both precision rifle ammo and, back in the day, handloading over 40,000 rounds of 9mm and 5.56 annually for competition.
He’s also a thermal and night vision expert, known for his obsession with high-end optics, and is rarely found without a camera or a guitar nearby. Whether he’s glassing a distant ridge, reviewing cutting-edge gear, or deep in legal research, True brings passion, precision, and grit to everything he does.
Experience:
– Professional Shooter – Sponsored 3-Gun & Multigun competitor with multiple titles and a foundation in long-range and sniper/tactical matches.– Firearms Instructor – Certified instructor with over 10,000 students trained face-to-face.– Elected Prosecuting Attorney – Attorney with real-world experience defending and prosecuting self-defense and gun-related cases.– Hunter & Rancher – Horseback hunter with a working ranch, passionate about elk, deer, predator, and backcountry hunting.– Reloading & Ballistics Expert – Precision reloader and former high-volume competition handloader.– Optics Authority – Known for his deep knowledge and unrelenting standards in optics, thermal, and night vision gear.– Outdoor Creative – Avid photographer, guitar player, and outdoorsman with a sharp eye for gear and storytelling.– 2A Advocate – Committed to protecting the Second Amendment and educating Americans about their rights and responsibilities.
The clip-on that offers a range of mounting heights, not just the standard 1.5″ or 40 mm, especially one that will go significantly lower, will win a big chunk of market.