I bought four of these to give away and they were all defective. See photo. When the inner arrow is aligned at 90, the outer arrow is closest to 1. It should be right at 0. He's not even close.
Digital multimeter RGK DM-12
6 Review
π¬οΈ Advanced 3-in-1 Indoor Air Quality Monitor with CO2/RH/Temp Data Logging and Audible Alarm - NDIR Sensor Technology
8 Review
Portable Handheld Manometer π for Accurate Pressure Differential Measurement
5 Review
π₯ Advanced Testo Wireless Hot Wire Anemometer Technology
4 Review