Review on 🌡️ 191 Soldering Temperature Tester: Accurate Soldering Iron Tip Thermometer with Digital Display by Dwayne Pore

Easy to use. The instructions say nothing about adding solder to the iron tip before using the sensor. However, if you watch Hakko's how-to video on these sensors and their thermometer, you'll see how they apply solder to the iron tip before checking the temperature, which I did. The temperature was within 2 degrees on my iron display so I was happy. Without adding solder to the iron tip, the temperature will be slightly lower. I think the solder helps make good contact with the sensor and is probably the right way to use it.