Review on 🔎 HDE Optimal Digital Infrared Tachometer for Professionals by John Destruction

I use it in my industrial electronics class. My adult students find it relatively easy to use. The instructions are pretty much useless.1. Stick a small piece of reflective tape on the shaft of the item to be tested or on the side of the item to be tested.2. Aim the laser at the shiny ribbon. Keep testing until you are satisfied with the speed of the test.3. Press the memory button once to look up or down, then again to look up or down. The display shows you the low and high value of the tested item. Notes: 1. I am not using the recommended battery, the regular 9V (alkaline) battery works best.2. Remove the batteries when not in use.3. Pay attention to the polarity when inserting the battery, if you insert it the wrong way around, you will destroy the meter. The small circle contact on 9v is positive.