Temperature values on the non-contact ir thermometer can be switched between celsius and fahrenheit.  The temperature measurement can also be locked to display on the non-contact thermometer's LCD screen for 60 minutes or as long as lock mode button is depressed.

Non-contact temperature measurements
The ideal distance in most applications for the non-contact ir thermometers is from 3.9 and 7.9 inces (100 and 200 mm); in this case, the size of the measurement spot equals approx. 0.1 to 0.3 inches (3 to 7 mm).  As the distance (D) from the object increases, the spot size (S) of the area measured by the non-contact thermometer becomes larger.  Make sure that the target is larger than the non-contact infrared thermometer's spot size.  The smaller the target, the closer you should hold the non-contact ir thermometer to it.  When accuracy is critical, make sure the target is at least twice as large as the non-contact infrared thermometer's spot size.

Emissivity
Inaccurate readings will result from using the non-contact infrared thermometers to measure shiny or polished metal surfaces like stainless steel or aluminum.  To compensate, cover the surface to be measured with masking tape or flat black paint.  Allow time for the tape to reach the same temperature as the material underneath it.  Use the non-contact thermometer to measure the temperature of the tape or painted surface.  When measuring a grill, for example, aim the non-contact ir thermometer at a portion of the grill that has been blackened by the high temperatures.  The non-contact thermometers cannot measure through transparent surfaces such as glass or plastic.  The non-contact infrared thermometers will measure the surface temperature of the transparent surface instead.  Steam, dust, smoke, etc., can prevent accurate measurement by obstructing the non-contact ir thermometer's optics.  Hold the non-contact infrared thermometer back and at an angle to ensure the most accurate measurements.

Applications
The TFI 500 Non-Contact Thermometer is a handy temperature measuring instrument for various measure and control tasks in the trade, the industry, and the laboratory.  Applications for the non-contact ir thermometer include fast, simple temperature measurements of liquids, motors, pipes, food, storage containers, received goods, supermarket areas, kitchens, and refrigerated rooms.  NOTE: When measuring liquid products, be sure to stir the product vigorously while using the non-contact infrared thermometer to measure the surface of the liquid.  Note: DO NOT submerge non-contact thermometers in water.

Non-contact Thermometers Specifications

Measurement range: -76 to 1400°F (-60 to +760°C)
Accuracy:
     ±2°F (±1°C) in environmental temperature of 77°F (25°C) and an object temperature of 59 to 95 °F (+15 to +35°C)
     ±2% of the measured value or ±3.5°F (±2°C) (whichever is higher) over the entire measurement range with an environmental temperature of 70 to 77°F (20 to 26°C)
Resolution: 0.1°F (0.1°C) at 14.2 to 391.8°F (-9.9 to 199.9°C), otherwise 2°F (1°C)
Reaction time (90%): approx. 1 second
Emission factor: 0.1 to 1.0
Ratio of distance to meas. spot: 30:1