International: +1.815.337.8555
US: 1.800.637.1623


Item Number: 35010
One year warranty
Patent Pending

Made In The USA



Before using this meter assure the area above the intended location of use is free from overhead obstructions such as tree branches or electrical wires. Contacting an overhead object could pose a safety risk to the user from falling debris. Contacting an overhead electrical wire could cause an electrocution hazard to the user.



Displays “Inversion Present” or “No Inversion” with intensity shown in degrees based on temperature measurements at 1 meter and 3 meter heights.


Measures accurate air temperature at boom height to meet label requirements.


Radiation shields around the temperature sensor limit errors due to solar or ground thermal radiation.


Auto detects when temperature readings are stable.


Includes NIST-Traceable Certificate for temperature accuracy.


Backlight on LCD for dawn/dusk or night operation.


Folds for easy transport and storage.


Convenient carry case included.

Range:0.0 to 150.0°F (-18.0 to 65.0°C)
Resolution:0.1°F (0.1°C)
Accuracy:+/- 0.36°F (0.2°C) absolute
+/- 0.18°F (0.1°C) for inversion intensity
Battery:Replaceable CR2032 lithium battery (included)
Provides 100 hours of ‘on’ time
Weight:1.0 lbs (0.45 kg)
Size:3.5”Dia x 23”L (8.9cm Dia x 58.4cm L) folded
2.75”Dia x 41.5”L (7cm Dia x 105cm L) deployed
Weatherproof:IP64 Rated


1. Temperature Sensor Inside Radiation Shields (Shown With Cover Removed)
2. Sliding Pole Lock
3. Pole Retaining Clip
4. LCD Display with Backlight
5. Control Buttons
6. Battery Cover (CR2032 Battery)
7. Ball Handle


Follow all chemical label instructions regarding where and when to measure and record weather conditions for each chemical you are applying. The information presented with this product is not intended to replace or override requirements set forth on pesticide or herbicide labels. If no specific label requirements exist then it is recommended that three inversion tests be made to assure accuracy of the inversion determination. These readings would ideally be made in different locations within the field and completed both before and after the application event.


Most smart cell phones attach location data including latitude and longitude values as well as exact time and date to every picture taken as part of the photo metadata. It is therefore recommended that a cell phone picture be taken of the display on the SpotOn® Inversion Tester to document the inversion or temperature display result. After a reading has been taken with the meter it will continue to be displayed on the meter’s LCD for one minute to allow time for a photo to be taken.


Unscrew the temperature sensor cover. Next unlatch the pole from the pole clip (3) of Fig. 1 using firm upward hand pressure as shown in Fig. 2. Then unfold the pole and move the sliding pole lock (2) of Fig. 1 fully over the flexible spring as shown in Fig. 1. When finished using the meter move the sliding pole lock back against the stop collar and refold the pole snapping it into the pole retaining clip (3) of Fig. 1 with firm hand pressure. Finally replace the temperature sensor cover to protect the radiation shields from dirt or impact.


While the meter is displaying a temperature on the screen, press both the On/Off and Go buttons simultaneously. This will cause the display to change from °F to °C or °C to °F.


Turn the meter ON and wait for the current temperature reading to display after the battery status screen. No other buttons need to be pressed to measure current air temperature. Hold the temperature sensor end (1) of Fig. 1 at boom height and wave it back and forth until you observe a stable temperature value on the LCD. Please note that a flashing temperature value indicates that the sensor is still adjusting to current air temperature. Continue to wave the sensor back and forth until the displayed temperature reading shows steady without flashing. This indicates a stable temperature reading.


Turn the meter ON and wait for the display to show current temperature, then press GO to enter the first inversion reading sequence. Follow the on-screen instructions to hold the ball end (7) of Fig. 1 at a height of 2 meters(6.5 feet). Use the Inversion Tester to set this height; it is 1 meter long so it can be used as a measuring stick by placing the shield end on the ground and noting the height of the ball end as shown in Fig. 3. Next raise the ball end until the shield end is at this noted 1 meter height as shown in Fig 4. This sets the ball end at the 2 meter(6.5 foot) elevation. Press the GO button to start the reading sequence for the lower temperature reading. While holding the ball end of the meter at 2 meters (6.5 feet) wave the sensor end back and forth quickly to improve air flow as shown in Fig 5. (vigorous waving leads to a faster response). Continue waving back and forth until the display beeps and shows “DONE”. Now flip the meter over so that the sensor end is pointing straight up towards the sky while continuing to hold the ball end at 2 meters (6.5 feet) as shown in Fig 6. Press the GO button to start the reading sequence for the upper temperature reading. Follow the previous waving and waiting instructions until this upper reading is complete. The display will now show either “INVERSION PRESENT!” or “NO INVERSION” based on the recorded temperature values as shown in Fig. 7. It will then show the inversion intensity in °C or °F. The display will continue to alternate between the inversion result and the intensity for one minute before it automatically shuts off.
Note: This meter will not capture a temperature reading until its software detects a stable value. Therefore “waving” time will be longer when the meter is placed in an environment significantly hotter or colder than where it was stored.


The inversion intensity is the actual temperature difference between the upper temperature reading the and lower temperature reading. It will display as a positive value when an inversion is present and as a negative value when there is no inversion. Under normal atmospheric conditions (no inversion) the intensity should show as a negative value of 0.5°F(0.3°C) or less. If an inversion is present then the intensity value will be a positive value between 0.1°F(0.1°C) and 5.0°F(2.8°C). Any inversion should be considered significant for applicators, with higher intensity values indicating a stronger inversion is present.


The LCD will show “REPLACE BATTERY!” when it is time to change the battery. There is no need to replace a battery with a reading of 25% or higher. Remove the screw cover (6) of Fig. 1 by rotating counter clockwise. A screwdriver may be required to loosen the cover. Gently pry out the old battery with a small knife or tiny screwdriver as shown in (8) of Fig. 8, being careful not to damage the battery holder. Replace with a new CR2032 lithium coin cell battery and replace the screw cover. Tighten the cover clockwise until the o-ring seal is slightly compressed.


Store the meter inside the included carry case with dust cover in place to keep dust from covering the temperature sensor or radiation shield. Dirt on the radiation shields can cause them to absorb more sunlight energy and therefore cause errors in the air temperature readings. Use a damp cloth to clean the radiation shields or meter body. Do not submerge meter in water because this could damage the electronics. An occasional spray of water will not damage the unit.


If the Red Sliding Pole Lock (2) of Fig. 1 won’t stay in place while waving, try the following: With the sliding pole lock in the folded position take a pair of pliers and gently squeeze the end of the red tube opposite of the spring. This will cause the brass tube inside to become slightly out-of-round which will allow it to grip on the spring when moved to the locked position.


Contact your local dealer for returns or repairs.


Share your name and email address for access to our 2023 Ag/Turf Catalog.

Thank You!