Few people will ever feel the need to invest in an AFR meter but if you do stay away from this one:
https://www.aliexpress.com/item/1005003599132669.html
After only 2 month it stopped working. I am not sure if the sensor or the instrument died - my guess would be the sensor because the instrument runs thru its initialization - but then only displays 3 dots in the middle of the screen and no values. We spent literally hours to check all the electrical contacts to make sure it wasn't the reason for this failure - to no avail.
https://www.aliexpress.com/item/1005003599132669.html
After only 2 month it stopped working. I am not sure if the sensor or the instrument died - my guess would be the sensor because the instrument runs thru its initialization - but then only displays 3 dots in the middle of the screen and no values. We spent literally hours to check all the electrical contacts to make sure it wasn't the reason for this failure - to no avail.
Also: although there are 2 meaningless 5-star reviews on the Aliexpress site for this product I seem to be unable to add my own review in spite of the fact that I purchased it. Ali is even worse than Amazon when it comes to faking reviews it seems.