I am really happy to have bought these. They work perfectly and always give me results that feel consistent and accurate based on how many carbs I have had in the last few days. Using them, I have been able to see how much damage "cheating" on my low carb diet really does. I've found that while a bite or two of something carb heavy doesn't make much of a difference, a whole day of cheating will drop my ketone levels to trace, and they wont come back the high levels that I normally have until 2-4 days later depending on just how many carbs I ate. Right now, I am using them to test just how many carbs I need to stay in high ketone levels that I want, while still being able to get a decent amount of fiber and vegetables. Right now I am eating 10-15 carbs per day, and always in one of the two highest ketones levels according to these strips, but I will be adding a few more carbs each day to find out what my limit should be. I will definitely be buying these again, and am very happy with my purchase.