At the Vector Optics booth at Shot Show 2026, I discovered the smallest thermal optic I’d ever seen, the Owlset HEIM ES X-Nano RSS08. This thermal optic has an ACRO and is sized between an enclosed pistol red dot and an EOTech holosight.
The RSS08 is powered by an 18280/CR2 battery and came with 3 cells in the box along with a USB-C combatible charger. Each cell is rated to run the unit for up to 3.5 hours (in standby/sleep mode). The unit can also be powered and recharged using a USB-C port.
The RSS08 is not just a thermal imager, but it is also a thermal camera, allowing the user to record video and photo stills. The unit has about 14-16GB of internal memory. The RSS08 model can be connected via WiFi to an Owlset mobile App to control the camera and to download files. Or you can download the files via the USB-C port to your computer.
Its 1.4″ LCD display screen is a touch display which allows for gesture controls and access to the menu. Two external control buttons allow additional access the menu and activate/deactivate the unit. The RSS08 offers 6 false-color modes to display hot/cold objects and 10 reticle options for targeting. The default PURE MODE setting must be deactivated before the reticles are available.
Nighttime, hand-held testing did reveal the unsuitability of using the RSS08 as a pistol optic. I was able to clearly ID human and varmint-sized objects in complete darkness over 100 yards away. But the rapid movement of the LCD screen under recoil would make it unreadable in rapid fire. On a rifle, it would necessitate very slow semi-fire. On a pistol slide, impossible.
Moreover, the light spill from the screen would easily give the user’s position away to another human. To an animal, this wouldn’t be as alarming as the noise we make walking around at night. And before using this thermal on a firearm, you should consult your local hunting and gun laws.
One major drawback to using the RSS08 as a combat or patrol optic is water. The RSS08 is IPX6 water-resistant, able to survive rain and water spills. But as anybody with a phone knows, moisture renders LCD touchscreens inoperable until they can be wiped dry.
Where I see this mini thermal being used is co-mounted to a red dot or other optic. The box comes with an ACRO to Picatinny adapter plate, and Vector Optics makes a selection of adapters. The RSS08 isn’t the firearms optic as I’d originally hoped, but it is a capable and affordable full-featured thermal camera.
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https://vector2007.com/VEOT-RSS08
SPECS
X-NANO RSS08
Infrared Resolution: 256×192 / 12μm
Frame Rate: 50Hz
Magnification: 0.5x /1x
NETD: ≤40 mK
Detection Range: ≤ 600m (656.17yds)
Recognition Range: ≤ 150m (164.04yds)
Angular Field of View: 13.5° × 10.1°
Focus Range: 5m – ∞
Display Screen: 1.4
Pseudo-Color Modes: White Hot, Black Hot, Hot Iron, Rainbow, Iron Red, Cold Color
Reticle: 10 Reticle Options with 5 Color Modes (Black / White / Red / Green / Yellow)
Weight: 123 g / 4.34 oz
Dimension: 51×43×46 mm / 2.01×1.69×1.81 in
Wi-Fi & App Support: Yes
Waterproof: IP66
Shockproof: 1000 G
Battery Type (Not Include): 16280, 900 mAh
Operating Duration: 3.5h
Charging Interface: USB Type-C, 5 V
Operating Temperature: -20°C to 60°C / -4°F to +140°F