If the apartment has a window, a mirror, or a glass door to the floor, it is better not to buy. Probably only our Ozmo 900 has the issue—not all of them. But, since Ecovacs will not have technical support in 2022, there is no one to question about this. The model would be perfect for our flat if the card memory feature could be disabled. But regrettably, the card needs to be manually reset before every cleaning. You need to pick up the phone and linger on it for a while before saying "Alice, start cleaning." I wasn't too bothered by the issue throughout the first month. I purchased a Xiaomi Dreame F9 with camera-based navigation after three months.