Very quiet, high 2 L capacity, small enough to put out of the way. My cats took to it very quickly. The only reason I didn’t give this five stars is that the users manual could be a little bit better. It was difficult for me to set up the connection to my net work, because there were some spots in the instructions that weren’t complete. Also, there was nothing in the users manual to tell me which side app I should place the charcoal filter in the filter holder.