Armasight Sidekick review: a 1x thermal monocular you can wear

By the OpticVerdict Editorial Team.
Research-based review · Updated 2026-10-03

How we reviewed it: a research-based review built from Armasight's own product pages for the Sidekick 320 and the Sidekick 640, the two OpticsPlanet listings and all 11 owner reviews on them (6 on the 320, 5 on the 640), read lowest rating first. We have not used this monocular ourselves; the score is our editorial opinion and owner ratings are shown attributed to their source. With 11 reviews in total, owner patterns here are small samples, and we give the number every time. Claims we could not confirm on Armasight's site are left out. See how we evaluate.

What the Sidekick is

The Sidekick is a handheld or helmet-mounted thermal viewer. It is not a riflescope. Armasight's spec tables and feature lists give 1x optical magnification with 1x to 4x digital zoom, an ULTEM composite body, three-button control, multiple color palettes, image detail enhancement, video recording and image capture, a compass, a battery status indicator, a USB-C interface for external devices and a USB video stream. Armasight lists no wireless connection on either model.

The two versions reviewed here share most of that. What changes is the thermal core and the lens: the 320 uses a 320x240 core behind a 9.1 mm fixed-focus lens, the 640 a 640x480 core behind a 19 mm manual-focus lens, which makes the 640 slightly longer and heavier (254 g against 214 g, both with eyecup and no battery, per Armasight). OpticsPlanet also lists a Sidekick 640 Pro 1-4x19mm as a separate product. It is a different model, and nothing on this page describes it.

Armasight describes both versions as "Designed and Assembled in the USA from U.S. and Global Component".

Why owners like it: small, light and a true 1x view

All 11 reviews across the two listings give three stars or more, and every one says they would recommend it. The most repeated praise is size and weight: three of the six Sidekick 320 reviews call it small or light and a fourth lists size and weight among its pros, and four of the five Sidekick 640 reviews describe it as small or light weight. The other point owners make is the 1x view. Because the image is not magnified, you can walk with it, which the most helpful positive review on the 320 puts plainly:

“It has a really wide FOV and a true 1x lens, so I can navigate the terrain without stumbling or falling.”

M King, most helpful positive review of the Sidekick 320, via OpticsPlanet

Owners also use it as a scanner before switching to a primary optic. One verified 640 owner describes it this way, and a verified 320 owner says it is much easier to scan with than the primary optic on a rifle.

“This is perfect for scanning your environment for targets.”

Dutch (NC), verified owner, Sidekick 640, via OpticsPlanet

The 320's limit: detection, not identification

Armasight rates the Sidekick 320 at 331 m detection, 85 m recognition and 53 m identification on a human sized target. Two of the six 320 reviews make the same point in their own words: the unit shows that something warm is there well before it shows what it is. A third, the most helpful negative review, faults the 320x240 resolution for demanding applications and calls it a thermal for use within 100 yards.

“It does lack the resolution to identify outside of approx 100yrds.”

Balloo (TX), verified owner, Sidekick 320, 3 stars, via OpticsPlanet

“Not a top-of-the-line thermal as it's 320x240 resolution just isn't good enough for demanding applications.”

Mike, most helpful negative review of the Sidekick 320 (3 stars), via OpticsPlanet

The second of the two, a verified owner, uses it to detect people on their property but says it is not particularly good at identification in the dark. If you hunt open fields and need to tell a coyote from a dog at range, that is the case for the 640.

Sidekick 640: more detail, a focusable lens, a higher price

The 640 keeps the same 1x view and nearly the same field of view (Armasight lists 24.16° x 17.37°), and puts a 640x480 core behind a 19 mm lens you focus by hand. Armasight rates it at 709 m detection, 177 m recognition and 111 m identification on a human sized target, roughly double the 320's figures on each line. The 640's five OpticsPlanet reviews average 4.6, with no rating below four stars. One verified owner moved up from the 320:

“I had a 320 unit before and this unit takes to the next level.”

Oldguns (OH), verified owner, Sidekick 640, via OpticsPlanet

The most helpful review on the 640 pairs it with a PVS14 on a bridge mount, and calls the ability to collimate and co-align the image crucial for what the reviewer calls a hybrid bino application. Armasight lists an "Ability to Shift Thermal Image to Collimate Sidekick Image with NVD when Bridged" among the features on both product pages. One verified 320 owner also reports pairing that unit with a pvs14.

The honest catches

Battery life. Armasight lists 1.5 hours on one CR123A and 5.5 hours on two CR123A batteries with the battery extender, at 20 C (68 F), for both models; the OpticsPlanet listings' feature lists say 1 hour on one CR123A at 20 degrees C. Three of the 11 reviews raise runtime: one 320 owner lists battery life as the only con, a verified 640 owner does the same, and a third 640 reviewer recommends a bigger power source.

“The single CR123 battery use is short lived, so you'll want to expand your power source for longer, sustained use.”

Lowspeed101 (ID), Sidekick 640, via OpticsPlanet

Armasight's in-the-box list for both models includes two CR123A batteries and a battery extender. The OpticsPlanet package lists name the two CR123A batteries but not the extender, so confirm what ships with your order.

The helmet mount is extra. Armasight lists a dovetail mini-rail included for helmet mounting "(with Optional Mount)", and says the Sidekick works with the Rayvn Group Modular Bridge Mount for use with a PVS-14, an MNVD or a second Sidekick, a line that ends "(sold separately)" on both product pages. One verified 640 owner gives the cost side:

“Be aware that helmet mounting options for this model are VERY limited and the Armasight mount is VERY expensive.”

Gunrunner72 (KY), verified owner, Sidekick 640, 4 stars, via OpticsPlanet

Small quirks, one owner each. The most helpful 640 review reports the controls freezing at first while the image kept working, cleared by removing power to force a reset, with settings kept afterwards. A verified 640 owner finds the USB cover comes off too easily and the paperwork in the box thin, and went to Armasight's website for the manual. Another 640 reviewer reports getting an email from Armasight with instructions for a software update after owning the unit for about three weeks. These are single reports, not patterns.

Trade-offs, plainly

• The 320 detects far but identifies close: Armasight's identification figure is 53 m, two of six 320 reviews say it struggles to identify at distance, and a third faults its resolution.
• Runtime on one CR123A is short (Armasight: 1.5 hours; OpticsPlanet listing: 1 hour); three of 11 reviews raise it.
• Helmet use needs a mount bought separately; one 640 owner calls the options very limited and the Armasight mount very expensive.
• It is a viewer, not a weapon sight, and magnification above 1x is digital zoom (Armasight: 1x optical, 1x to 4x digital).
• The 640 costs considerably more than the 320 for its higher-resolution core and focusable lens.
• No wireless connection on either model (Armasight lists Wireless: None).

Key specifications: Sidekick 320 vs Sidekick 640

Specifications are Armasight's, from its Sidekick 320 and Sidekick 640 product pages (not the Sidekick 640 Pro). The OpticsPlanet listings give different dimensions and a 1-hour runtime; where they differ we print Armasight's figures. Detection, recognition and identification ranges are Armasight's ratings for a human sized target, not field measurements. No editorial award is claimed.

Buying notes

Both OpticsPlanet listings carry a "Government Export Restriction" notice. Armasight's own export policy page states: "Some Armasight item(s) are subject to the International Traffic in Arms Regulations (ITAR), and export is strictly prohibited without authorization or a license issued by the U.S. Department of State's Directorate of Defense Trade Controls." We do not interpret export rules; read the retailer's notice before you order. On warranty, Armasight's product pages list 3 years with registration; the Armasight warranty text on the OpticsPlanet listings gives 1 year standard for thermal imaging devices and 3 years extended when you register the product.

Should you buy it?

• Buy the Sidekick 320 if you want a light 1x thermal for walking your property, checking for animals close in, or a budget hybrid setup next to a night vision monocular, and you will carry spare batteries.
• Buy the Sidekick 640 if you need to identify what you are seeing at longer range, or want a sharper image for a bridged night vision and thermal setup, and the price gap is acceptable.
• Look at a magnified handheld if you glass open country from one spot: our best thermal monocular guide covers monoculars with more base magnification.
• Look at a thermal scope if you want to aim with thermal: see the best thermal scope guide.

FAQ

More thermal and night vision: best thermal binoculars · best night vision monocular · Wilcox G24 helmet mount · thermal vs night vision.