Guide IR TA421 product image

Guide IR TA421

The TA421 is a thermal clip-on made by Guide IR and is part of the TA Gen 2 series.


The TA421 features a crisp 25mm f/1.1 objective lens focusing the available thermal radiation. The field of view on this thermal clip-on is 14.9 by 11.2 degrees. It features a 4 times digital zoom to enlarge your subject. The eye relief distance is measured at 10mm and the exit pupil diameter measures 20mm.

Behind the lens of the TA421 you can find the (uncooled, 17 micrometer) 384 x 288 pixels thermal core refreshing the image at 50Hz. The thermal contrast (NETD) of this thermal clip-on is <40mK and it's operating within the 8µm to 14µm infrared spectrum.

The physical dimensions of this thermal clip-on read 153 x 57 x 79mm (lwh) weighing in at 475 grams. This device is rated IP67. It handles dust, shocks and water (splashes). It's rated for operating in temperatures between -30°C and 50°C.

The TA421 is built to be used in scanning and surveillance, hunting adventures and police operations.



  • Extended Battery Life
  • Easy Installation, No Re-zeroing Required
  • PureIR Image Algorithm
  • Six color palettes
  • Rugged and Durable (IP67 Rated)
  • Wireless remote control


Lens25 mm
Eye relief distance10 mm
Exit pupil diameter20 mm
Optical zoom1 x
Digital zoom4 x
FOV (h/v)14.9 ° / 11.2 °
Thermal typeUncooled
Sensor resolution (h/v)384 pixels / 288 pixels
Pixel pitch17 µm
Sensitivity40 mK
Spectral range8 µm / 14 µm
Display resolution (h/v)1024 pixels / 768 pixels
Refresh rate50 Hz
Image polarityWhite Hot, Black Hot, Red Hot, Green Hot, Iron Red, Blue Hot
Output screen colorFull color
Video formatsLEMO Interface
Startup time10 seconds
Package contentsExternal eyepiece, Adapter ring, Picatinny rail, Bluetooth remote control, 7-pin LEMO to USB and AV cable
Dimensions (l/w/h)153 mm / 57 mm / 79 mm
Weight475 g
Number of batteries1
Battery life7 hours
Operating temperature-30 °C / 50 °C
Storage temperature-45 °C / 70 °C
Environmental ratingIP67
Law enforcement
Search & rescue
Fire fighting

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 264 meters 66 meters 33 meters
Person 931 meters 232 meters 116 meters
Vehicle 2254 meters 563 meters 281 meters

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

More in TA Gen 2 series