It worked for 20-25 measurements and now it doesn't turn on or the screen turns on occasionally without measuring. Thankfully, Skroutz gave me my money back. You always have to remove the battery because otherwise the button gets stuck and it will drain it!

It is completely fake in terms of construction (what do you expect for this money, you will tell me) Chinese in all its glory. Be careful not to leave the battery inside the device, I left it and in three days it ate a 9-volt battery and oxidized it. Two stars because it also did a measurement.... What do we expect to get for €14.50.....

I tried it in two functions..
Speeds
Heat
The last one has the ability to measure power losses from a bulb through temperature.
It does what it says.

To measure rotations, a sticker must be attached 1cm above the rotating object. I bought it for such use, and I found it to work perfectly and give accurate values without deviation. With 10 euros, I did my job flawlessly, so 5 stars.