Above entry-level thermal monocular which contains a lot of features for its size. - ATN ODIN LT 640, 1-4x19mm Compact Thermal Viewer Sensor, Multiple Patterns & Color Options Reticle

Having done some initial research before buying this monocular I wanted something that was to be used both for hand-held and head-mounted use. I also liked the fact it did not have a built-in battery since thermals like digital night vision have a significant low battery life when compared to analog night vision.

The first thing you'll notice about this monocular is its size and weight. It's extremely small and lightweight while still capable of 4x zoom. I opted for the 640 model since I would be using the 4x zoom and didn't want to lose resolution when trying to ID from afar.

After using it with the OEM head mount bracket I did not like the fact it's secured by a tension screw. If your planned use is beyond just viewing this stationary than look towards investing in a quality mount (I'd recommend from Noisefighters). The included rail on the monocular is not a true mini-rail like on the MUM-14 or Sionyx Opsin, but it's close enough. For retention I suggest positioning the monocular at the desired distance and marking that position the rail. Drill a hole so the set screw of the mount secures and dummy cord it with either shock or 550 cord.

Operation-wise this monocular has an easy to use interface system once you read the manual and use it a couple of times. It has white-hot and black-hot modes and you can cycle between 1x, 2x and 4x. If you're using this very briefly than CR123s will be fine, otherwise if you intent on prolonged use get the extended battery pack that charges via USB-C. Other than the extended battery pack also invest in a quality padded case as the included one offers no real protection.

Pro = Small size, lightweight, easy to use, extended battery life with optional addon

Con = Head mount lacks secure retention (no quality aftermarket support)