Two bits of advice: 1. I checked out all the cheap ones, and Zacurate was the only brand I could find that was under $50 and had actually been properly tested

Two bits of advice: 1. I checked out all the cheap ones, and Zacurate was the only brand I could find that was under $50 and had actually been properly tested for accuracy. 2. If you buy one from Amazon ("ships from and sold by Amazon.com") or that specific brand from "Beyond Med Shop" (which is owned by Zacurate), you won't get a counterfeit.