Guide IR TK631 product image

Guide IR TK631

The TK631 is a thermal monocular made by Guide IR and is part of the TK series.


The TK631 houses a clear 35mm f/1 objective lens collecting thermal radiation. The default field of view on this thermal monocular measures 12.5 by 9.4 degrees. It has a 8 times digital zoom to enlarge (parts of) the image. The exit pupil diameter measures 10mm.

Behind the lens of the TK631 you can find the (uncooled, 12 micrometer) 640 x 480 pixel microbolometer refreshing the image at 50Hz. The NETD of this thermal monocular is <30mK and it's operating within the 8µm - 14µm infrared wavelengths.

The measurements of this thermal monocular read 214 x 65 x 71mm (l/w/h) and the scale reads 560 grams. This device is rated IP66. It's protected against dust, shocks and water (splashes). It handles temperatures between -10°C and 50°C.

The TK631 can be utilized in surveillance, hunting trips and law enforcement (police, border patrol etc.).



  • HD Display (1280 x 960 pixels)
  • Integrated Laser pointer with flashlight
  • Anti-Fog Eyepiece
  • Up to 8x Digital Zoom
  • PiP (Picture in Picture) mode
  • 6 color palettes
  • IP66 protection
  • Live streaming


Lens35 mm
Diopter adjustment-4 +2
Exit pupil diameter10 mm
Optical zoom2 x
Digital zoom8 x
FOV (h/v)12.5 ° / 9.4 °
Thermal typeUncooled
Sensor resolution (h/v)640 pixels / 480 pixels
Pixel pitch12 µm
Sensitivity30 mK
Spectral range8 µm / 14 µm
Display resolution (h/v)1280 pixels / 960 pixels
Refresh rate50 Hz
Image polarityBlack Hot, White Hot, Adjustable Red Hot, Iron Red, Blue Hot, Green Hot
Output screen colorFull color
Video formatsMicro HDMI Out
Startup time2 seconds
Package contentsPower adapter, USB cable (Type C), Micro HDMI cable, Lens cap, Wrist strap, , Shoulder strap, Quick start guide
Dimensions (l/w/h)214 mm / 65 mm / 71 mm
Weight560 g
Number of batteries2
Battery life4.5 hours
Law enforcement
Search & rescue
Fire fighting
Operating temperature-10 °C / 50 °C
Storage temperature-30 °C / 60 °C
Environmental ratingIP66

DRI Ranges

DRI stands for Detection, Recognition and Identification and is based on the widely used Johnson's criteria.

  • Detection Detect if an object is present
  • Recognition See what type of object it is (i.e. person, vehicle, airplane)
  • Identification For example see if someone is a friend or foe
Detection Recognition Identification
Rabbit 525 meters 131 meters 65 meters
Person 1847 meters 461 meters 230 meters
Vehicle 4472 meters 1118 meters 559 meters

Please note that these values are calculated, always consult the manufacturer for official range numbers.


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