I bought 2 of this for my grandparents as an upgrade to the ones they had from China. I chose this because it had a good price and a decent rating. But after receiving the product, the sensors turned out to be even less accurate than the old ones. I might have just have received defective units so I just simply returned the items with no hassle. Besides the sensors, the device looked nice and the usage was pretty intuitive. My grandparents would have totally liked the device is the main sensor actually worked.