I have followed the manual to the letter. The English on the instruction is not very good and open to interpretation. For example it is not clear if during the forehead reading, the device should touch the forehead or not, and how long the movement should last. It also says the ear reading is more accurate. I tried 3 people and had 33 to 35 degrees. For forhead, it was 36 to 37 which actually seems more accurate.
The ear reading varies quite a bit between readings while the forehead give a consistent reading.
The device allows you to calibrate with a more accurate device but this does not help due to significant inconsistency between the ear and forhead readings.
eBay has these devices at half the price but I thought products from Amazon are more reliable. Clearly I was wrong.
In my experience Amazon US has provided very good value money and quality products throughout the years, quite opposite to what we get from Amazon Australia, and just like everything else that they sell us.