50:1 Ultra-Wide-Range Infrared Thermometer with "K" Port and Adjustable Emissivity


50:1 Ultra-Wide-Range Infrared Thermometer with "K" Port and Adjustable Emissivity

The #IRT850K laser thermometer has the optics needed to measure high temperatures safely—from a distance. It also has the features and measurement range needed for demanding industrial applications, including operation and maintenance of furnaces and heat exchangers.


Best For:



  • Ultra-wide measurement range
  • "K" port
  • Adjustable emissivity
  • Min/max/avg/dif memory
  • Stores/recalls 24 data sets (measured temperature + emissivity setting)
  • Measurement lock mode
  • Adjustable high and low alarms
  • Dual targeting lasers
  • °F/°C and laser on/off switches
  • Large backlit dual-readout LCD
  • White LED flashlight
  • Auto power off
  • Tripod mount
  • Made in Taiwan (TAA-compliant)
  • NIST calibration is available
  • Specifications


    • Distance-to-spot (D:S) ratio: 50:1
    • IRT measurement range: -76° to 2732°F (-60° to 1500°C)
    • IRT measurement accuracy: ±1.8°F (±1°C) from 59° to 95°F (15° to 35°C); ±(2% of reading or 3.6°F/2°C), whichever is greater, from -27° to 59°F (-33° to 15°C) and from 95° to 273
    • "K" port measurement range: -83° to 2552°F (-64° to 1400°C)
    • "K" port measurement accuracy: ±(2% of reading +3.6°F/2°C) or ±5.4°F (3°C), whichever is greater
    • Measurement resolution: 0.1° below 1000°; 1° at and above 1000°
    • Emissivity: Adjustable from 0.1 to 1.0 in 0.01 increments, with factory default of 0.95
    • Display size and type: 2 in. (51mm) diagonal backlit LCD with 0.5 in. (13mm) high digits on main readout
    • Response time: < 1 second
    • Operating temperature: 32° to 122°F (0° to 50°C) @10 to 90% RH
    • Auto power off: After 1 minute of inactivity in IRT mode, or 12 minutes of inactivity in "K" port mode
    • Weight: 13.6 oz. (386g)
    • Power source: Two "AAA" batteries (not included)


    • Custom hard plastic carrying case
    • 1-year limited warranty


    • 7.99 x 7.76 x 1.85 in. (203 x 197 x 47mm)


    What is the distance to spot (D:S) ratio?

    The distance to spot (D:S) ratio is the ratio of the size of the area where the temperature is being measured in relation to the distance from the target. For instance, if the IRT has an 8:1 distance-...
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    Which IRT has the highest temperature detection range?

    The IRT5000 has the highest temperature detection range. [392° to 4352°F (200° to 2400°C)]

    Which IRT has the greatest low temperature detection range?

    The IRT850K can detect temperatures as low as -76°F (-60°C).

    Which IRT has the greatest distance-spot (D:S) ratio? Which has the smallest?

    The IRT5000 has a distance-spot (D:S) ratio of 100:1. Conversely, the IRT built into the HT50 has a D:S ratio of 2:1.

    What is emissivity?

    The emissivity of the surface of a material is its effectiveness in emitting energy as thermal radiation. Knowing the emissivity of a material can help increase the accuracy of the IRT’s reading...
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    Is it better to have an IRT with a fixed or adjustable emissivity?

    The default emissivity setting for all the IRT’s is 0.95. This setting will produce fairly accurate readings for the majority of items you will typically measure. Being able to set the emissivit...
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    Which IRT’s have adjustable emissivity?

    The following models have adjustable emissivity: IRT8, IRT105, IRT659K, IRT730K, IRT850K.

    If my IRT has a fixed emissivity, how can I take measurements on materials that don’t have 0.95 emissivity?

    If you are able, cover the area you intend to measure with black electrical tape. Wait a minute and then scan that area. The emissivity of the tape is 0.95.

    Can an IRT be used to measure body temperature?

    We do not carry an IRT which can be used for body temperature. You would need an IRT designed with medical applications in mind.

    Can you take the temperature of an item through a transparent material? Example: Taking the temperature of an item on the other side of a window.

    The IRT cannot take the temperature of one item through another material. If you aim the IRT at a window, it will give you the temperature of the window and not items on the other side of the window.

    Can an IRT give air temperature readings?

    IRT’s only give temperature readings of solid materials. You can scan an item to get an approximation of the room temperature, but the IRT will not give an actual ambient temperature reading.

    Prop 65

    ⚠ WARNING: This product can expose you to chemicals including di2-ethylhexylphthalate (DEHP), which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.