I bought this product to use in wine, juice, etc. It does the job for me, but I was a bit annoyed when I first got it. Before your first use, you need to calibrate it with a buffer solution that is not provided with the kit. My question is: why not? There is another kit here on Amazon that offers everything combined. I spent a long time going from shop to shop and couldn't find any around my London postcode (EC1, N1). So I had to order it online and guess what? Wait for the delivery time. Very inconvenient indeed.