HTI HT-A4 product image


The HT-A4 is a thermal monocular made by HTI and is part of the HT-A series.


The HT-A4 comes equipped with a clear 24mm lens to capture thermal signatures. The FOV on this thermal monocular measures 14.9 x 11.2 degrees. It comes with a 4x digital zoom to get additional details.

Inside the housing of the HT-A4 you'll find the (uncooled, 17µm) 384 by 288 pixel thermal sensor with a refresh rate of 50Hz. The NETD of this thermal monocular is <50mK and it's operating between the 8µm - 14µm infrared wavelengths.

The measurements of this thermal monocular are 187 x 69 x 68mm (l/w/h) and weighs 440g. This device is rated IP66. It's protected against dust, shocks and water (splashes).

The HT-A4 is built for surveillance, hunting trips, law enforcement (police, border patrol etc.) and SAR (Search and Rescue) operations.



  • Available with 3 lens options; 19mm, 25mm (default), 35mm
  • Long battery life (Up to 6 hours)
  • 50Hz refresh rate
  • Video-out to external screen (Optional)
  • On-board picture storage


Lens24 mm
Optical zoom4 x
Digital zoom4 x
FOV (h/v)14.9 ° / 11.2 °
Thermal typeUncooled
Sensor resolution (h/v)384 pixels / 288 pixels
Pixel pitch17 µm
Sensitivity50 mK
Spectral range8 µm / 14 µm
Display resolution (h/v)1024 pixels / 768 pixels
Refresh rate50 Hz
Image polarityWhite hot, black hot, iron red, rainbow
Output screen colorFull color
Startup time3 seconds
Dimensions (l/w/h)187 mm / 69 mm / 68 mm
Weight440 g
Number of batteries1
Battery life6 hours
Law enforcement
Search & rescue
Fire fighting
Storage temperature-20 °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 254 meters 63 meters 31 meters
Person 894 meters 223 meters 111 meters
Vehicle 2164 meters 541 meters 270 meters

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

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