AGM Sidewinder Thermal Monocular Review

In this AGM Sidewinder Thermal Monocular Review, we will focus on two of the new AGM Sidewinder Thermal monoculars: the TM35-640 and the TM25-384. AGM Global has made remarkable progress in just a few years, expanding their product line from compact thermal rifle scopes to a comprehensive selection of thermal rifle scopes, laser range-finding thermal scopes, and now premium handheld thermal monoculars.

For night hunters, a premium thermal scanner is a game-changer.  The introduction of the Sidewinder series has fulfilled the demands of hunters for a premuim AGM thermal monocular. AGM has met the demand with not one, but four top-tier handheld thermal monoculars that make up the Sidewinder series.

Our aim is to provide you with information that common to all the Sidewinder thermal monoculars, compare the performance of two of them in real-world scenarios, and assist you in determining which one better suits your hunting or observation requirements.

Common Features of Both Sidewinder Models

The Sidewinder series encompasses high-quality handheld thermal monoculars designed specifically for hunting and security applications. These models incorporate advanced technology, with a 640×512 or 384×288 twelve-micron thermal sensors and 1024×768 OLED displays. Both of our test units featured a 2-16X magnification.


AGM Sidewinder TM35-640 Battery Compartment

Powered By 18650 Batteries

They are powered by inexpensive rechargeable 18650 batteries, so you can easily carry your backup power in your pocket. Two batteries are provided with the scope and will power the scope for 6-8 hours.The battery must be removed from the scope for charging in the supplied battery charger.

Of course you have to power the unit down to change the battery. I has a small battery compartment door built into the housing with a locking latch. Just side the locking latch to unlock, pop open the cover and replace the battery. It takes about a minute from power down until you are scanning again.

An external 5V power bank (battery pack) can be used via a USB to USB-C connector but you probably won’t need it if you charge the two supplied batteries before your hunt. The device has 64 Gig’s of storage for onboard video and audio recording or image capturing. It has internal Wi-Fi for live video streaming and video/image recording via the AGM App.

Noteworthy improvements in the Sidewinder series compared to the AGM Taipan monoculars include superior temperature sensitivity with a sub-20 milli-kelvin (NETD) rating across the entire product line and larger objective lenses. The lower NETD really makes animals stand out from their background. 

Additionally, the Sidewinders offer a more durable body, and video recording and audio recording. Like all AGM thermal optics, the Sidewinder has a 5-year warranty.

It’s important to note that the Sidewinder series complies with California’s Proposition 65 warning, indicating that it meets the necessary safety standards.

AGM Sidewinder Thermal Monocular Comparison

Every hunter desires the best value for their money, seeking the finest thermal monocular within their budget. AGM offers four excellent options, starting with the TM25-384 priced under $2000. Moving up to the TM35-384 costs a little more at $2195. The Sidewinder TM35-640 has a price of $2995, and the TM50-640 is available at $3495. Sidewinder thermal monoculars are covered by a 5-year warranty.

The price increase from 384 to 640 resolution is $1000, but the improvement in image quality is substantial. Better processors and larger Germanium lenses come at a premium cost, which is true across the industry, not just with AGM.  AGM has priced these scopes slightly lower than some of their competitors, but they have not compromised on image quality or features.

Field Of View – The Forgotten Factor

When comparing the monoculars, it is crucial to focus on the field of view. Speaking from personal experience, I prioritize a wider field of view over a higher base magnification, especially when it comes to scanning for coyotes. The key objective during scanning is detection, particularly when calling predators.

TM25-384 2X, FOV – 55 feet at 100 yards
TM35-384 3X, FOV – 39 feet at 100 yards
TM35-640 2X, FOV – 65 feet at 100 yards
TM50-640 2.5X, FOV – 45 feet at 100 yards

When comparing the 640 resolution models, it’s worth considering that the TM50-640 might offer a slightly better image quality due to its larger lens and 0.5X higher base magnification. However, by choosing the TM35-640, you’ll gain an almost 50% wider field of view, and only loose .5X of magnification.

If you’re using the scanner to locate hogs, the field of view may not be of utmost importance. However, if you’re scanning for coyotes responding to a call, a narrow field of view can be a significant disadvantage.

If your rifle scope has a very low power setting, opting for a higher base magnification in your thermal monocular may prove beneficial. Additionally, since scanners have a wide range of applications beyond hunting, a 2.5X base magnification might better suit your needs compared to a 2X scanner.

Technical Specifications of the Sidewinder Series:

AGM Side Winder Specs


Hunting With AGM Sidewinder Monoculars

The image quality of both Sidewinders is outstanding. It’s important to note that the TM35-640 offers a significantly superior image, but this is expected as it features a more robust thermal sensor and comes with a higher price tag.

I was thoroughly impressed with the image quality of both these Sidewinder binoculars. At these price points, it’s unlikely that you’ll find any other thermal monoculars on the market with such exceptional image quality. Let’s take a look at some videos to showcase just how impressive the images are.

These videos were made during warm and humid summer nights in Georgia, so you can expect a much better image during cooler, less humid conditions in the fall and winter months.

Sidewinder TM35-640


Sidewinder TM25-384

By observing these videos featuring cows, hogs, and deer, you’ll gain an understanding of the identification range for various animals. While coyotes are smaller, with careful observation of their movement, and experienced hunter can differentiate them from small deer at distances of up to 400 yards with the TM35-640.

In terms of image quality, I would rate the TM35-640 as better than some of the competition within the same price range and objective size, though it may not surpass other thermal monoculars with 50mm objectives. Also keep in mind that the video images are not as good as the image actually is.

Regarding the TM25-384, I would rate it as one of the best images I’ve seen in a 384×288 resolution binocular. The black hot palette works exceptionally well, and the identification range extends to 200-250 yards, and even farther in wide open fields.

The Sidewinders also excel in terms of ergonomics and button layout. The button layout is on top so it is completely ambidextrious. The buttons have different shapes so they are easier to recognize by touch in the dark. The lightweight design and shape of the monocular make it easy to use, and reduces fatigue during long scanning sessions while hunting.

The rubberized exterior provides a secure grip, although I do wish it had a side hand strap to aid in orienting the monocular. I found myself needing a bit of extra time to align the buttons to the top. Nevertheless, there is an attachment loop for a lanyard at the bottom of the eyepiece. When using a lanyard it helps align the monocular and makes it easy carry while hunting.

Color Palettes

The Sidewinders offer four excellent palettes: black-hot, white-hot, red-hot, and fusion (yellow & purple). I personally appreciate all of these palettes as they work exceptionally well for spotting game. While I typically prefer white-hot for scanning, the black-hot palette is my favorite in both the TM25-384 and TM35-640. The black hot palette in both models seems smoother with better details than the other color palettes. I think black hot extends my ID range over the other palettes.

The 2X base magnification is ideal for my hunting needs, specifically for coyotes and hogs. It provides the necessary magnification for scanning open ranges without being too powerful for close-in operations in wooded areas.

Daytime Use

An aspect that most people overlook is the advantage of using a thermal scanner for daytime hunting. I often stalk up to my stand or feeders in the early morning and late afternoon using my thermal monocular. It allows me to spot and identify animals in the shadowy areas of the woods long before they are visible to the naked eye or even binoculars. Scanning a brushy hillside just before sunrise and after sunset reveals game that would otherwise go unnoticed. I never embark on a deer hunt without my thermal monocular. Once you try it, I bet you won’t either.

Power In Your Pocket

One of the greatest advantages of the Sidewinder is its use of replaceable, rechargeable 18650 batteries. By keeping a couple of these small batteries in your pocket, you’ll never run out of power and they only cost a few bucks each. The competition's propiatery rechargable batteries cost around $100 each.

There’s no need to worry about recharging an internal battery before your hunt. Affordable and reliable power is always at your fingertips, and can be changed very easily and quickly. Two very good 18650 batteries are provided with the scope. The batteries must be removed and charged with the provided battery charger.

AGM Sidewinder Overall Performance

The only mechanical issue we encountered during our hunts was the objective lens cover popped off a couple of times. You might want to tether it to the scope to prevent loss.

It takes a little longer to power up than some other brands, but the convenient standby feature takes that concern away after you start your hunt.

Overall, I like these the AGM Sidewinders Monoculars very much and would definitely recommend them to hunters. I think you will be well served by either of these AGM Sidewinder Thermal Monoculars we tested.

The images are very good compared to other monoculars on the market today, and the design and features will make them a pleasure to use in the field. They fit comfortably in your hand and the button layout is as good as you will find.

Key Features of the Sidewinder Series:

Superior Thermal Sensitivity: The Sidewinders boasts one of the highest thermal sensitivities in their class, with a NETD (Noise Equivalent Temperature Difference) rating of less than 20 millikelvin. This exceptional sensitivity ensures accurate and reliable thermal imaging.

Advanced Image Processing: Equipped with Digital Detail Enhancement, digital Noise Reduction, and the NLM (Non-Local Means) algorithm, the Sidewinders offer advanced image processing capabilities for optimal image quality.

High Frame Rate: With a 50 Hz image frame rate, these monoculars deliver smooth and real-time thermal imaging, reducing motion blur and ensuring clear visuals.

High-Resolution OLED Display: The Sidewinders feature a 1024×768 resolution OLED display, enhancing image clarity and detail.

Ample Memory and Functionality: The built-in 64 GB memory module provides ample storage for video recording and snapshot capturing. The monoculars also support Wi-Fi connectivity, facilitating data transfer and sharing.

Versatile Digital Zoom: Users can take advantage of the 1×, 2×, 4×, and 8× digital zoom options to magnify the captured images for a closer look.

Rechargeable Battery: The Sidewinders come with two replaceable and rechargeable 18650 Li-Ion batters, providing up to 7 hours of continuous operation. They also have external power supply capability for extended usage.

Waterproof Design: With an impressive waterproof rating, these monoculars are built to withstand challenging weather conditions, providing peace of mind to users in various environments.

5-Year Warranty: The Sidewinder series is backed by a 5-year warranty, ensuring customer satisfaction and support. Package Contents:

The Sidewinder monoculars come with the following items;
Battery Charger
USB Cable Power Adapter (US and EU plugs included)
Two 18650 Rechargeable Batteries
Lens Cloth
Wrist Strap
Carrying Case
User Manual Protective Bag

To purchase a new AGM Sidewinder Thermal Monocular, visit or call Jason or Hans at Outdoor Legacy at (877)350-1818. They will answer all your questions and make sure you get the right scope for your hunting needs. For the latest news about Night Vision Optics, subscribe to the most informative show on Youtube, the Late Night Vision Show. Hosts Jason Robertson and Joel Miller will keep you up to date on Night Vision Optics and entertain you with some great hunting videos. Also please visit our featured Youtube channels Outdoor Legacy on Youtube, HansETX, and The Old Deer Hunters for great hunting videos and thermal optic reviews.