I think it is accurate. I tested it on 4 different olive oils and it gave me different acidity values (Refined extra virgin: 0.5, Refined virgin: 1.3, Bulk that I recently got in Kefalonia from a friend: 0.6, and Bulk that I bought last year upon recommendations: 2.4!). I don't want to blame the seller for the last one. It may not be the seller's fault. I stored it for 1 year in a stainless steel container. As I consumed it, it is natural that air entered the container which oxidized it and raised the acidity. What matters is that the test works and the instructions in the accompanying note are clear.

Easy to use with the company's video,
don't expect the color to become intense...
The results in already measured oil, from the olive mill,
were the same...

It helped me understand which oil is good and bad for me.
I confirmed the measurements with bottled olive oil and the measurements were accurate.
Although the usage instructions are detailed, the product could be made even more user-friendly.

Easy to use with clear instructions (in proper Greek and with colorful illustrations). The accuracy of the measurement was comparable to what we had been told at the olive oil mill. It is also important for me that the whole kit has the image of a well-crafted product and not a semi-amateur one. I recommend it.