Bests & Worsts Reviews from Amazon

I'm a physician. I bought the device to have at home during the covid pandemic, figuring that in case anyone in the house felt ill, we could check their oxygen saturation and decide if we needed to seek care immediately. The unit sat in its box since we bought it four month ago, until last night when I wasn't feeling very good. I used the device and on multiple readings my oxygen saturation varied between 87% and 91%. I went to the emergency room, where my oxygen saturation was 97%. I came back home and tried the device again; it read 91%. We checkedmy wife's pulse ox, and with no symptoms or medical problems she read only 93%. So, this gadget doesn't live up to its reputation