I read a lot of reviews about glass washer robots, this one was almost everywhere in the top. After the purchase, I was a little disappointed - I tried to use it on fairly clean windows from the inside. As a result - a lot of divorces and mostly from the tape. It is written that it is impossible to wet the rag too much: the tape slips off, it is so. But I still tried to moisten it in some places and it got better, but washing should be done several times. But after I tried the robot on the outside, I realized that the purchase was successful. I have 18 floors and panoramic windows, it's just unrealistic to wash normally, although there were various attempts. I was afraid that he would just smear the dirt, but everything worked out - on the contrary, he cleaned the dirt well (even an already dirty rag did not leave super terrible stains). Of course, it’s very far from ideal, but in my case it’s super, because I get about the same result from self-cleaning, but with great effort. I decided that I would always wet the rag (just wet it, and not just spray it from the sprayer) and use it from the outside (on the inside it only makes it worse :)))