Okay, I meant to write this review months ago, but I put it off and forgot about it. By the way, I enclosed a few pictures to make my point. So take a look at them to see what I'm talking about.First, I really, really wanted these test strips to be good! The name brand, Ketostix, are very expensive, like 4 times the price, since the 50 strip retail pack costs about double that of the "Perfect Keto Strips", containing half the amount. The first batch was dubiously accurate, but serviceable, with some "fixing" on my part. But I was able to at least use them. I will explain the "fixing" in a minute.I ordered another one for the purposes of a low price backup about a month later based on the incredible discounted price, under the "You get what you paid for" mantra. I would have been fine if they were like the first, since the saving are quite substantial. However, that second batch was, quite simply, worthless.I probably should have returned them, but for $7.99, I couldn't honestly be bothered going through the hassle of the Amazon return procedures, not to mention boxing it up and mailing it back, even with the return postage paid by Amazon. The problem with the second batch is that they were a light shade of purple almost from the second I received them. I had actually lent the first batch to a friend, which is why I had opened the second one.If you look at the first picture I uploaded, you will see a shot of a bunch of the dry, never used purple "Perfect Ketone Testing Strips" above the name brand Ketostix. Notice that the color of the store bought one is neutral, indicating no ketones, of course, since it has not been passed through a stream of urine. The other ones look like they have been tested and all positive, even though, like the Ketostix strip, they were not used.They don't change color at all from that purple, by the way, or I might have been willing to overlook the dry color, though probably not. Because even if they seemed to work, can I really trust the accuracy of a stick that starts out showing positive for ketones even while dry?Okay, so that's the scoop on the second, defective batch.For the first batch, I mentioned above that I had to sort of apply a little fix. I want to call your attention to pictures 2 and 3 of the ones I uploaded. The smaller bottle, which is the Ketostix while the larger one is the Perfect Ketone Test Strips. Take a look at the color chart on the larger bottle. Notice that the colors are just off enough to render reading them almost impossible for all but the deepest levels of ketosis. I mean, of course, deep purple is deep purple, right? No ambiguity there. The caveat here is that MANY people like me don't bother trying to get deep into ketosis to turn it so dark purple that you don't even really need the chart.When I am dieting, I always hover around "trace" and "small" for the most part. Unless I am being more aggressive in that phase of my diet. Now looking at those pics, notice that the colors on the one I am reviewing are darker and richer than the Ketostix. This may look great on the package, and maybe even is a good selling point, BUT it is a terrible chart to measure ketones, particularly at a lower level of ketosis. When I hold a currently in-use (read: peed on) stick against the chart that came with these, it is maddeningly impossible to tell where I'm at. Because the colors for "Negative," "Trace," and even small are so pink. Yes even the "Negative" is a little pink!Look at the side-by-side comparison. Note that the second comparison picture, the vertical one, is much more illustrative of what I'm talking about. Even in ketosis, my stick looks like it is some sort of combination of all three colors. Its maddening. When I line up the strip (either the Ketostix or the "good" batch I first ordered in May) with the chart on the Ketostix, it is easy and unequivocal what state of ketosis I am in. The difference is startling actually.Anyway, I would be wary of this brand, and if you really want to save the money, simply make sure you have an old, possibly even empty, bottle of ketostix and use that to measure your ketosis even when using Perfect Ketone Test Strips. Unless you get a batch like my second one, which was useless. Then either grin and bear it, or send it back.As I said, assuming you get a good batch, the sticks are serviceable, but someone at the company that makes these really needs to fix the color chart on the bottle so its more like Ketostix!Oh, and one more thing: If you look at the last picture, the expiration date on the bottle is 2021, which means that even if I opened them just now, and not the 8 months ago I actually did, they should still be good.