Purchase purely for monitoring of covid.
I'm not sure about the accuracy.. The thing is, I use it every time with repetitions, and I take the average of the readings to be sure.
Usually after the first test, which is always a different reading from what follows,
all the rest usually agree, but not always.
I don't get extreme differences, but it's different to play between 96-98 and 94-96 or 88-90.

Also, it has a nice menu, as it has completion notification beeps and threshold value notifications - which can also be set by the user. Otherwise, you can disable it. Also, the indications on the screen are not "monobands" but with the press of a button they change the reading address, so they can be read from wherever you look or whichever hand you use.

I won't bother criticizing a device that costs 25€, while objectively valid ones for professionals cost 80-100€, nor do I have experience with other devices of similar cost to compare, and I believe that very few have them here, so look for similar reviews.

If you have a serious health problem, prefer something else, but look directly 2 classes above.
If you simply fear covid and want to do monitoring, it seems fine.