This thing can never be "accurate". Proper instantaneous measurements for radiation require more than a good detector. The operator is part of the equation.<p>Say you have two pieces of fish in front of you. Answering the question "which one is more radioactive" requires more than holding a device over each for a couple minutes. You have to think of the flux, the surface area of the fish visible to the detector, the orientation of the detector, any background sources, the mass of each piece and most importantly the distance between the fish and the detector. That cannot be built into a hand-held consumer product. Absent that, these devices will only scare people.<p>Note the pic in the OP showing the detector plugged in via an extension cable. I'd bet that they moved it around until magically it's measurement lined up with the other device.<p>Also, low levels of radiation are nothing to be concerned with. The linear no-threshold model (the direct relationship between radiation and cancer) is no longer considered appropriate when discussing very low levels.